Glossary of Physics Terms
<<<<<<< HEAD This glossary provides ISO 11179-compliant definitions for all 200 concepts in the high school physics course. Each definition is precise, concise, distinctive, and non-circular. ======= This glossary contains ISO 11179-compliant definitions for all physics concepts covered in this course. Definitions are designed to be precise, concise, distinct, non-circular, and appropriate for high school students with Algebra II and Geometry prerequisites.
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Acceleration
The rate of change of velocity with respect to time, measured in meters per second squared (m/s²).
<<<<<<< HEAD Example: When a car speeds up from rest to 60 mph, it experiences positive acceleration; when braking, it experiences negative acceleration (deceleration).
Acceleration-Time Graphs
A graphical representation showing how acceleration varies over time, with acceleration on the vertical axis and time on the horizontal axis.
Example: In a graph of constant acceleration, the line is horizontal; when acceleration changes, the graph shows a slope or curve.
Action-Reaction Pairs
Two forces that are equal in magnitude, opposite in direction, and act on different objects according to Newton's Third Law.
Example: When you push against a wall, the wall pushes back on you with an equal and opposite force.
Acoustic Resonance
The amplification of sound waves when their frequency matches the natural frequency of a vibrating system or cavity.
Example: Blowing across a bottle creates a resonant tone at a specific frequency determined by the bottle's shape and size.
Example: A car accelerates from rest to 60 mph in 5 seconds, experiencing a constant acceleration throughout this period.
Acceleration-Time Graphs
Graphical representations showing how acceleration varies over time, with time on the horizontal axis and acceleration on the vertical axis.
Example: An acceleration-time graph for a rocket launch shows a spike during engine ignition, then drops to zero during coasting.
Acoustic Resonance
The phenomenon where a sound-producing system vibrates with maximum amplitude at specific frequencies corresponding to its natural modes.
Example: When you blow across a bottle opening, it produces a specific tone because the air column resonates at its natural frequency.
Action-Reaction Pairs
Two forces that are equal in magnitude, opposite in direction, and act on different objects as described by Newton's Third Law.
Example: When you push against a wall, the wall pushes back on you with an equal force in the opposite direction.
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Amplitude
The maximum displacement of a wave or oscillating object from its equilibrium position.
<<<<<<< HEAD Example: In a pendulum, the amplitude is the maximum angle the pendulum reaches from vertical; larger swings have greater amplitude.
Angled Projection
The launch of an object at an angle between 0° and 90° to the horizontal, creating a parabolic trajectory.
Example: A soccer ball kicked at a 45° angle follows a curved path combining horizontal and vertical motion components.
Angular Acceleration
The rate of change of angular velocity with respect to time, measured in radians per second squared (rad/s²).
Example: When a spinning figure skater pulls in their arms, they experience angular acceleration as their rotation rate increases.
Angular Displacement
The angle through which an object rotates about an axis, measured in radians or degrees.
Example: When a wheel completes one full rotation, its angular displacement is 2π radians or 360 degrees.
Angular Frequency
The rate of change of phase in oscillatory motion, equal to 2π times the frequency, measured in radians per second.
Example: A pendulum with a frequency of 2 Hz has an angular frequency of approximately 12.57 rad/s.
Angular Momentum
The product of an object's rotational inertia and angular velocity, representing the quantity of rotational motion.
Example: A spinning ice skater has angular momentum; when they pull their arms in, their rotation rate increases to conserve angular momentum.
Angular Velocity
The rate of change of angular displacement with respect to time, measured in radians per second (rad/s).
Example: A Ferris wheel rotating at 0.1 rad/s completes one full revolution every 62.8 seconds.
Atwood Machine
A system consisting of two masses connected by an inextensible string passing over a pulley, used to study Newton's laws and tension.
Example: An Atwood machine with a 5 kg mass on one side and a 3 kg mass on the other demonstrates unbalanced forces and acceleration.
Banked Curves
Roadways or tracks tilted at an angle to the horizontal to provide centripetal force through the normal force component.
Example: NASCAR tracks are steeply banked curves that allow cars to maintain high speeds through turns without excessive friction.
Beats
The periodic variation in amplitude that occurs when two waves of slightly different frequencies interfere.
Example: When two guitar strings are slightly out of tune, you hear a "wah-wah" beating sound at the frequency difference between them.
Center of Mass
The point at which an object's entire mass can be considered concentrated for analyzing translational motion.
Example: The center of mass of a uniform rod is at its midpoint; for a hammer, it's closer to the heavy head.
Centripetal Acceleration
The acceleration directed toward the center of circular motion, equal to the square of velocity divided by radius.
Example: When you swing a ball on a string in a circle, it experiences centripetal acceleration directed toward your hand.
Centripetal Force
The net force directed toward the center of circular motion that causes an object to follow a curved path.
Example: Earth's gravity provides the centripetal force keeping the Moon in its nearly circular orbit.
Charging by Contact
The transfer of electric charge between objects when they touch, resulting in both objects having the same type of charge.
Example: When a charged rod touches a neutral metal sphere, electrons transfer until both objects reach the same charge state.
Charging by Friction
The transfer of electrons between two materials rubbed together, leaving one positively charged and one negatively charged.
Example: Rubbing a balloon on your hair transfers electrons to the balloon, leaving your hair positively charged and the balloon negatively charged.
Charging by Induction
The redistribution of charge within an object caused by the presence of a nearby charged object, without direct contact.
Example: Bringing a negatively charged rod near a neutral conductor causes positive charges to move toward the rod's side.
Example: A pendulum swinging 10 centimeters to each side of center has an amplitude of 10 centimeters.
Angled Projection
Projectile motion where an object is launched at an angle to the horizontal, resulting in both horizontal and vertical velocity components.
Example: A soccer ball kicked at a 45-degree angle follows a parabolic path before landing downfield.
Angular Acceleration
The rate of change of angular velocity with respect to time, typically measured in radians per second squared (rad/s²).
Example: A spinning figure skater pulling in their arms experiences angular acceleration as their rotation rate increases.
Angular Displacement
The angle through which an object rotates about a fixed axis, measured in radians or degrees.
Example: A wheel completing one full rotation undergoes an angular displacement of 2π radians or 360 degrees.
Angular Frequency
The rate of change of the phase of a sinusoidal waveform, equal to 2π times the frequency, measured in radians per second.
Example: A mass oscillating on a spring with a frequency of 2 Hz has an angular frequency of 4π rad/s.
Angular Momentum
The rotational analog of linear momentum, calculated as the product of rotational inertia and angular velocity.
Example: A spinning ice skater has angular momentum that remains constant when no external torques act on them.
Angular Velocity
The rate of change of angular displacement with respect to time, typically measured in radians per second (rad/s).
Example: A merry-go-round completing one rotation every 10 seconds has an angular velocity of π/5 rad/s.
Atwood Machine
A simple mechanical system consisting of two masses connected by a string passing over a pulley, used to study Newton's laws.
Example: In a physics lab, students use an Atwood machine to measure gravitational acceleration by analyzing the motion of unequal masses.
Banked Curves
Curved roadways or tracks tilted at an angle to the horizontal, allowing vehicles to navigate turns at higher speeds safely.
Example: NASCAR race tracks have steeply banked curves that enable cars to maintain high speeds through turns without excessive friction.
Beats
A periodic variation in sound intensity produced when two waves of slightly different frequencies interfere.
Example: When tuning a guitar, you hear beats between the string being tuned and a reference pitch until they match.
Center of Mass
The point where an object's mass can be considered concentrated for analysis of translational motion.
Example: A properly balanced mobile hangs horizontally because it's suspended at its center of mass.
Centripetal Acceleration
The acceleration directed toward the center of a circular path that changes the direction of an object's velocity without changing its speed.
Example: The moon experiences centripetal acceleration toward Earth as it orbits, keeping it in its circular path.
Centripetal Force
The net force directed toward the center of a circular path that causes an object to follow that curved trajectory.
Example: When you swing a ball on a string in a circle, the tension in the string provides the centripetal force.
Charging by Contact
The transfer of electric charge between objects when they physically touch, resulting in both objects having the same type of charge.
Example: A charged metal rod touching a neutral metal sphere transfers some charge to the sphere.
Charging by Friction
The generation of electric charge through rubbing two different materials together, causing electrons to transfer from one to the other.
Example: Rubbing a balloon on your hair transfers electrons, allowing the balloon to stick to a wall.
Charging by Induction
The redistribution of charge in an object caused by the presence of a nearby charged object without direct contact.
Example: A charged rod brought near a neutral electroscope causes the leaves to separate temporarily without touching.
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Coefficient of Friction
A dimensionless value representing the ratio of friction force to normal force between two surfaces.
<<<<<<< HEAD Example: Ice on steel has a coefficient of friction around 0.02, while rubber on dry concrete is approximately 0.8.
Color Addition
The process of combining different wavelengths of light to produce new colors, following the RGB (red-green-blue) model.
Example: Overlapping red and green spotlights creates yellow light on a white screen.
Color Subtraction
The selective absorption of certain wavelengths by pigments or filters, allowing only specific colors to be transmitted or reflected.
Example: A cyan filter absorbs red light and transmits blue and green, making white light appear cyan.
Concave Lenses
Diverging lenses that are thinner in the center than at the edges, causing parallel light rays to spread outward.
Example: Eyeglasses for nearsighted people use concave lenses to diverge light before it enters the eye.
Concave Mirrors
Converging mirrors that curve inward like the interior of a sphere, capable of forming both real and virtual images.
Example: Makeup mirrors use concave surfaces to magnify your reflection when you're close to them.
Conductors
Materials that allow electric charge to flow freely due to the presence of mobile electrons.
Example: Copper wire is an excellent conductor used in electrical wiring; metals generally conduct electricity well.
Conservation of Angular Momentum
The principle that total angular momentum remains constant in an isolated system with no external torques.
Example: When a spinning figure skater pulls their arms inward, they spin faster to conserve angular momentum.
Conservation of Charge
The principle that the total electric charge in an isolated system remains constant over time.
Example: During any charging process, the total positive and negative charges remain balanced; charge is transferred, not created or destroyed.
Conservation of Energy
The principle that total energy in an isolated system remains constant, though it may transform between different forms.
Example: A falling apple converts gravitational potential energy into kinetic energy, with the total mechanical energy remaining constant (ignoring air resistance).
Conservation of Momentum
The principle that total momentum in an isolated system remains constant when no external forces act on it.
Example: In a collision between two billiard balls, the total momentum before impact equals the total momentum after impact.
Conservative Forces
Forces for which the work done depends only on initial and final positions, not on the path taken, allowing potential energy definition.
Example: Gravity is conservative; lifting a book directly or along a ramp to the same height requires the same work against gravity.
Constructive Interference
The superposition of waves where crests align with crests and troughs with troughs, producing increased amplitude.
Example: Two speakers playing the same frequency create louder sound at positions where waves arrive in phase.
Convex Lenses
Converging lenses that are thicker in the center than at the edges, causing parallel light rays to converge at a focal point.
Example: Magnifying glasses and camera lenses use convex surfaces to focus light and create enlarged images.
Convex Mirrors
Diverging mirrors that curve outward, always producing virtual, upright, and reduced images.
Example: Store security mirrors are convex, providing a wide field of view to monitor large areas.
Coulomb's Law
The principle that electric force between two point charges is proportional to the product of charges and inversely proportional to the square of distance.
Example: Doubling the distance between two charged particles reduces the electric force between them to one-quarter of its original value.
Critical Angle
The angle of incidence in a denser medium beyond which total internal reflection occurs at the boundary with a less dense medium.
Example: Light traveling through glass hits the glass-air boundary at angles greater than about 42° and reflects internally rather than refracting out.
Cross Product
A vector operation that produces a vector perpendicular to two input vectors, with magnitude equal to the area of the parallelogram they form.
Example: The torque vector is the cross product of position and force vectors, pointing along the rotation axis.
Damped Harmonic Motion
Oscillatory motion in which amplitude decreases over time due to energy dissipation from resistive forces.
Example: A playground swing gradually comes to rest as air resistance and friction at the pivot remove energy from the system.
Decibel Scale
A logarithmic scale for measuring sound intensity, where each 10 dB increase represents a tenfold increase in intensity.
Example: Normal conversation is about 60 dB, while a rock concert can exceed 110 dB, representing over 100,000 times more intensity.
Destructive Interference
The superposition of waves where crests align with troughs, producing reduced or zero amplitude.
Example: Noise-canceling headphones generate sound waves that destructively interfere with ambient noise.
Diffraction Grating
An optical component with many parallel slits or grooves that disperses light into its component wavelengths through interference.
Example: A CD's surface acts as a diffraction grating, separating white light into rainbow colors when viewed at different angles.
Dimensional Analysis
A mathematical technique using unit relationships to check equation validity and convert between measurement systems.
Example: Converting 60 mph to m/s requires multiplying by conversion factors: 60 miles/hour × 1609 m/mile × 1 hour/3600 s = 26.8 m/s.
Dispersion
The separation of light into different colors due to wavelength-dependent refraction in a medium.
Example: A prism spreads white light into a rainbow spectrum because blue light refracts more than red light.
Displacement
A vector quantity representing the straight-line distance and direction from an initial position to a final position.
Example: Walking 3 blocks east, then 4 blocks north results in a displacement of 5 blocks northeast, not 7 blocks total distance.
Distance
A scalar quantity representing the total length of path traveled, regardless of direction.
Example: Running around a 400-meter track covers a distance of 400 meters but results in zero displacement if you return to the start.
Doppler Effect
The change in observed frequency of a wave due to relative motion between source and observer.
Example: An ambulance siren sounds higher pitched as it approaches you and lower pitched as it moves away.
Dot Product
A scalar operation that multiplies two vectors to produce a number equal to the product of their magnitudes and cosine of the angle between them.
Example: Work is the dot product of force and displacement vectors, maximized when they point in the same direction.
Dynamic Equilibrium
A state where an object moves with constant velocity because the net force acting on it equals zero.
Example: A skydiver falling at terminal velocity experiences dynamic equilibrium as air resistance balances gravitational force.
Efficiency
The ratio of useful output energy to total input energy, typically expressed as a percentage.
Example: An electric motor with 80% efficiency converts 80 joules of electrical energy into 80 joules of mechanical work for every 100 joules input.
Elastic Collisions
Collisions in which both momentum and kinetic energy are conserved, with no energy converted to other forms.
Example: Collisions between billiard balls are nearly elastic, with balls bouncing apart with minimal energy loss.
Elastic Potential Energy
Energy stored in deformed elastic materials that can be recovered when the material returns to its original shape.
Example: A compressed spring stores elastic potential energy equal to (1/2)kx², where k is spring constant and x is compression distance.
Electric Charge
A fundamental property of matter that causes electromagnetic interactions, existing in positive and negative forms.
Example: Electrons carry negative charge (-1.6 × 10⁻¹⁹ coulombs), while protons carry equal positive charge.
Electric Field
A region around charged objects where electric forces act on other charges, represented by force per unit charge.
Example: The electric field around a positive charge points radially outward and weakens with distance.
Electric Field Lines
Visual representations of electric fields showing direction and relative strength through line density.
Example: Field lines emerge from positive charges and terminate on negative charges; closer spacing indicates stronger fields.
Electric Force
The attractive or repulsive interaction between charged objects, calculated using Coulomb's Law.
Example: Two electrons repel each other with an electric force that decreases as they move farther apart.
Example: Ice on steel has a coefficient of friction around 0.02, explaining why ice skating is so smooth.
Color Addition
The process of combining colored light beams to produce new colors, where red, green, and blue are primary additive colors.
Example: Stage lighting uses red, green, and blue lights that can combine to create white light or any color.
Color Subtraction
The process of removing specific wavelengths from white light through absorption by pigments or filters.
Example: A cyan filter absorbs red light and transmits blue and green, demonstrating subtractive color mixing.
Concave Lenses
Lenses that are thinner in the center than at the edges, causing parallel light rays to diverge.
Example: Eyeglasses for nearsightedness use concave lenses to help focus distant objects correctly on the retina.
Concave Mirrors
Curved mirrors with a reflecting surface that curves inward, capable of focusing light and producing magnified images.
Example: A makeup mirror is concave, producing an enlarged, upright image of your face when held close.
Conductors
Materials that allow electric charge to flow freely due to loosely bound electrons.
Example: Copper wires are excellent conductors, making them ideal for electrical circuits.
Conservation of Angular Momentum
The principle stating that angular momentum remains constant in a closed system when no external torque acts.
Example: A figure skater spins faster when pulling in their arms because angular momentum is conserved.
Conservation of Charge
The fundamental principle that the total electric charge in an isolated system remains constant over time.
Example: When you rub a balloon on your hair, the negative charge gained by the balloon equals the positive charge left on your hair.
Conservation of Energy
The principle stating that the total energy in an isolated system remains constant, though it may transform between different forms.
Example: A roller coaster converts gravitational potential energy to kinetic energy and back as it moves through the track.
Conservation of Momentum
The principle stating that the total momentum of an isolated system remains constant when no external forces act.
Example: In a collision between billiard balls, the total momentum before impact equals the total momentum after.
Conservative Forces
Forces for which the work done in moving an object between two points is independent of the path taken.
Example: Gravity is a conservative force—lifting a book to a shelf requires the same work regardless of the path.
Constructive Interference
The combination of two or more waves where their amplitudes add together, producing a wave with greater amplitude.
Example: When two water wave crests meet, they combine through constructive interference to create a higher crest.
Convex Lenses
Lenses that are thicker in the center than at the edges, causing parallel light rays to converge at a focal point.
Example: A magnifying glass is a convex lens that focuses sunlight to a point hot enough to start a fire.
Convex Mirrors
Curved mirrors with a reflecting surface that bulges outward, producing reduced, upright virtual images.
Example: Store security mirrors are convex, providing a wide-angle view of the entire room.
Coulomb's Law
The mathematical relationship describing the electric force between two charged objects as directly proportional to the product of their charges and inversely proportional to the square of the distance between them.
Example: Doubling the distance between two charged particles reduces the electric force between them to one-fourth its original value.
Critical Angle
The angle of incidence in the denser medium above which total internal reflection occurs at the boundary with a less dense medium.
Example: Fiber optic cables use critical angles to keep light trapped inside by total internal reflection.
Cross Product
A vector operation that produces a third vector perpendicular to two input vectors, with magnitude equal to the product of their magnitudes and the sine of the angle between them.
Example: Torque is calculated as the cross product of the position vector and force vector.
Damped Harmonic Motion
Oscillatory motion in which the amplitude gradually decreases over time due to energy loss from resistive forces.
Example: A car's shock absorbers create damped harmonic motion, quickly reducing oscillations after hitting a bump.
Decibel Scale
A logarithmic scale used to measure sound intensity level, where each 10-decibel increase represents a tenfold increase in intensity.
Example: A whisper measures about 30 decibels, while a rock concert can reach 120 decibels.
Destructive Interference
The combination of two or more waves where their amplitudes subtract, producing a wave with reduced or zero amplitude.
Example: Noise-canceling headphones create sound waves opposite in phase to ambient noise, causing destructive interference that reduces unwanted sounds.
Diffraction Grating
An optical device with many closely spaced parallel slits that separates light into its component wavelengths through interference.
Example: A CD surface acts as a diffraction grating, producing rainbow patterns when white light reflects off it.
Dimensional Analysis
A mathematical technique using units of measurement to check equations and convert between different unit systems.
Example: Converting speed from miles per hour to meters per second requires dimensional analysis with conversion factors.
Dispersion
The separation of light into its component wavelengths due to the dependence of refractive index on wavelength.
Example: Sunlight passing through a prism separates into a rainbow due to dispersion.
Displacement
A vector quantity representing the straight-line distance and direction from an object's starting position to its ending position.
Example: Walking 3 blocks north, then 4 blocks east results in a displacement of 5 blocks northeast.
Distance
A scalar quantity measuring the total length of the path traveled by an object, regardless of direction.
Example: Running once around a 400-meter track covers a distance of 400 meters, even though your displacement is zero.
Dot Product
A vector operation that produces a scalar by multiplying the magnitudes of two vectors and the cosine of the angle between them.
Example: Work is calculated as the dot product of force and displacement vectors.
Doppler Effect
The change in observed frequency of a wave when there is relative motion between the source and the observer.
Example: A train whistle sounds higher pitched as it approaches and lower pitched as it moves away.
Dynamic Equilibrium
A state where an object moves with constant velocity because all forces acting on it are balanced.
Example: A parachutist falling at terminal velocity is in dynamic equilibrium with gravity and air resistance balanced.
Efficiency
The ratio of useful output energy to input energy, typically expressed as a percentage.
Example: An electric motor with 80% efficiency converts 80 joules of electrical energy into 64 joules of mechanical work.
Elastic Collisions
Collisions in which both momentum and kinetic energy are conserved.
Example: Billiard balls colliding on a pool table approximate elastic collisions, bouncing apart with minimal energy loss.
Elastic Potential Energy
Energy stored in a deformed elastic object, such as a compressed spring or stretched rubber band.
Example: A compressed spring stores elastic potential energy that can launch a toy car when released.
Electric Charge
A fundamental property of matter that causes it to experience electromagnetic force, existing in two types: positive and negative.
Example: Rubbing a balloon creates an excess of electrons, giving it a negative electric charge.
Electric Field
A region around a charged object where other charged objects experience an electric force.
Example: The space around a charged balloon creates an electric field that can attract small pieces of paper.
Electric Field Lines
Imaginary lines used to visualize electric fields, pointing in the direction of the force on a positive test charge.
Example: Electric field lines radiate outward from a positive charge and inward toward a negative charge.
Electric Force
The push or pull experienced by charged objects due to their electric charges.
Example: Two electrons repel each other with an electric force because both carry negative charge.
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Electric Potential
The electric potential energy per unit charge at a point in an electric field, measured in volts.
<<<<<<< HEAD Example: A 12-volt battery maintains a 12-joule per coulomb potential difference between its terminals.
Electric Potential Energy
Energy stored in the configuration of charged objects due to their positions in an electric field.
Example: Separating opposite charges increases electric potential energy, like lifting a mass increases gravitational potential energy.
Electromagnetic Spectrum
The complete range of electromagnetic radiation organized by wavelength or frequency, from radio waves to gamma rays.
Example: Visible light occupies a narrow band (400-700 nm) within the vast electromagnetic spectrum that includes X-rays and microwaves.
Energy Diagrams
Graphical representations showing how potential and kinetic energy vary with position or time in a system.
Example: An energy diagram for a pendulum shows kinetic energy maximized at the bottom and potential energy maximized at the ends of the swing.
Equilibrium
A state where net force equals zero, resulting in either rest or constant velocity motion.
Example: A book resting on a table is in equilibrium as the table's upward force balances the book's downward weight.
Error Analysis
The systematic examination of measurement uncertainties and their propagation through calculations.
Example: Measuring a length as 15.2 ± 0.1 cm indicates the true value lies between 15.1 and 15.3 cm with reasonable certainty.
Field Strength
The magnitude of force per unit charge or per unit mass in electric or gravitational fields, respectively.
Example: Earth's gravitational field strength at the surface is approximately 9.8 N/kg, meaning each kilogram experiences 9.8 newtons of force.
Example: A 9-volt battery maintains a 9-joule energy difference per coulomb of charge between its terminals.
Electric Potential Energy
The energy stored in a system of charged objects due to their positions in an electric field.
Example: Separating opposite charges requires work, increasing their electric potential energy like lifting a mass increases gravitational potential energy.
Electromagnetic Spectrum
The complete range of electromagnetic waves organized by wavelength or frequency, from radio waves to gamma rays.
Example: The electromagnetic spectrum includes visible light (a tiny portion), radio waves, microwaves, infrared, ultraviolet, X-rays, and gamma rays.
Energy Diagrams
Graphical representations showing how potential energy and total energy vary with position for a system.
Example: An energy diagram for a pendulum shows potential energy highest at the ends of the swing and kinetic energy highest at the bottom.
Equilibrium
A state in which all forces acting on an object are balanced, resulting in zero net force.
Example: A book resting on a table is in equilibrium with gravity pulling down and the table pushing up with equal force.
Error Analysis
The systematic study of uncertainties in measurements and their propagation through calculations.
Example: When measuring a pendulum's period, error analysis accounts for reaction time uncertainty and calculates the resulting uncertainty in calculated gravity.
Field Strength
The magnitude of electric field at a point, equal to the force per unit charge, measured in newtons per coulomb.
Example: Near a Van de Graaff generator, field strength can be strong enough to make your hair stand on end.
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Focal Length
The distance from a lens or mirror to its focal point where parallel rays converge or appear to diverge from.
<<<<<<< HEAD Example: A magnifying glass with a 10 cm focal length focuses sunlight to a point 10 cm from the lens.
Force
A vector quantity representing an interaction that causes or tends to cause a change in an object's motion.
Example: Pushing a shopping cart with 50 newtons of force causes it to accelerate in the direction of the push.
Forced Oscillations
Periodic motion sustained by an external driving force applied to an oscillating system.
Example: Pushing a child on a swing at regular intervals maintains oscillations that would otherwise dampen due to friction.
Free Fall
Motion under the sole influence of gravity, with acceleration equal to g regardless of mass.
Example: A dropped feather and hammer fall at the same rate in vacuum, both accelerating at 9.8 m/s² downward.
Frequency
The number of complete cycles or oscillations occurring per unit time, measured in hertz (cycles per second).
Example: A pendulum completing 2 swings per second has a frequency of 2 Hz or 0.5 seconds per cycle.
Friction
A contact force that opposes relative motion or attempted motion between surfaces.
Example: Friction between brake pads and rotors converts a car's kinetic energy into thermal energy, causing it to slow down.
Graphical Analysis
The interpretation of physical relationships through visual representation in graphs and charts.
Example: A position-time graph with constant positive slope indicates motion at constant velocity in the positive direction.
Gravitational Potential Energy
Energy stored in an object due to its position in a gravitational field, equal to mgh near Earth's surface.
Example: A 10 kg object raised 5 meters gains 490 joules of gravitational potential energy (10 kg × 9.8 m/s² × 5 m).
Grounding
The process of connecting a charged object to Earth, allowing excess charge to flow to or from the ground.
Example: Lightning rods provide a grounding path for atmospheric charge, protecting buildings from lightning strikes.
Harmonics
Integer multiples of a fundamental frequency that occur in standing waves and musical instruments.
Example: A guitar string vibrating at 440 Hz (A4) also produces harmonics at 880 Hz, 1320 Hz, and higher multiples.
Hooke's Law
The principle that spring force is proportional to displacement from equilibrium, expressed as F = -kx.
Example: Compressing a spring with k = 100 N/m by 0.1 m requires 10 newtons of force and stores 0.5 joules of elastic potential energy.
Horizontal Projection
The launch of an object horizontally with zero initial vertical velocity, creating a parabolic trajectory.
Example: A ball rolled off a table edge maintains constant horizontal velocity while accelerating downward under gravity.
Example: A magnifying glass with a 10-centimeter focal length focuses sunlight at a point 10 centimeters from the lens.
Force
A vector quantity representing a push or pull that can cause an object to accelerate, measured in newtons.
Example: Pushing a shopping cart with 50 newtons of force accelerates it forward.
Forced Oscillations
Oscillatory motion driven by an external periodic force rather than occurring naturally.
Example: Pushing a child on a swing at regular intervals creates forced oscillations.
Free Fall
Motion under the sole influence of gravity, where all objects accelerate downward at the same rate regardless of mass.
Example: A feather and hammer dropped on the Moon fall at the same rate because there's no air resistance.
Frequency
The number of complete oscillations or wave cycles occurring per unit time, measured in hertz (Hz).
Example: Middle C on a piano has a frequency of 261.6 Hz, meaning the string vibrates 261.6 times per second.
Friction
A force that opposes the relative motion or attempted motion between surfaces in contact.
Example: Friction between your shoes and the ground allows you to walk without slipping.
Graphical Analysis
The interpretation of physical relationships by examining graphs of related quantities.
Example: The slope of a position-time graph reveals an object's velocity.
Gravitational Potential Energy
Energy stored in an object due to its position in a gravitational field, calculated as mass times gravitational acceleration times height.
Example: A 10-kg boulder on a 5-meter cliff has 490 joules of gravitational potential energy.
Grounding
The process of connecting a charged object to Earth, allowing excess charge to flow away and neutralize the object.
Example: Lightning rods protect buildings by grounding them, providing a safe path for electric charge to reach Earth.
Harmonics
Standing wave patterns that occur at integer multiples of a system's fundamental frequency.
Example: A guitar string vibrates at its fundamental frequency and higher harmonics simultaneously, creating its distinctive tone.
Hooke's Law
The principle stating that the restoring force in a spring is directly proportional to its displacement from equilibrium.
Example: Stretching a spring 5 centimeters requires twice the force needed to stretch it 2.5 centimeters.
Horizontal Projection
Projectile motion where an object is launched horizontally, having initial horizontal velocity but zero initial vertical velocity.
Example: A marble rolled off a table edge has horizontal motion while simultaneously falling vertically.
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Impulse
The product of force and the time interval over which it acts, equal to the change in momentum.
<<<<<<< HEAD Example: An airbag increases collision time, reducing force on passengers while delivering the same impulse to stop their motion.
Impulse-Momentum Theorem
The principle that impulse equals change in momentum, expressed as FΔt = Δ(mv).
Example: Catching a baseball with bent arms (longer time) reduces force compared to catching with stiff arms, though impulse remains the same.
Inclined Plane
A flat surface tilted at an angle to the horizontal, used to analyze forces and motion in two dimensions.
Example: A 30° ramp decomposes weight into components parallel (causing sliding) and perpendicular (creating normal force) to the surface.
Inclined Plane as Machine
A simple machine that reduces force required to raise an object by increasing the distance over which force is applied.
Example: A 10-meter ramp to reach 2 meters height requires one-fifth the force of lifting directly, but force acts over five times the distance.
Index of Refraction
A dimensionless number indicating how much light slows and bends when entering a medium, equal to c/v.
Example: Water has an index of refraction of 1.33, meaning light travels at 75% of its vacuum speed in water.
Inelastic Collisions
Collisions in which momentum is conserved but kinetic energy is not, with some energy converting to other forms.
Example: A car crash is inelastic; vehicles crumple and heat up as kinetic energy converts to deformation and thermal energy.
Inertia
The tendency of an object to resist changes in its state of motion, proportional to mass.
Example: A bowling ball's large inertia makes it difficult to start rolling or stop once moving, compared to a tennis ball.
Infrasound
Sound waves with frequencies below the lower limit of human hearing (approximately 20 Hz).
Example: Elephants communicate using infrasound below 20 Hz, allowing signals to travel several kilometers through the ground.
Example: An airbag increases collision time, reducing the force of impulse on passengers during a crash.
Impulse-Momentum Theorem
The principle stating that the impulse applied to an object equals its change in momentum.
Example: Catching a baseball with a glove demonstrates the impulse-momentum theorem as the glove increases stopping time to reduce impact force.
Inclined Plane
A flat surface tilted at an angle to the horizontal, used as a simple machine to raise objects with less force over a longer distance.
Example: A wheelchair ramp is an inclined plane that reduces the force needed to reach an elevated entrance.
Inclined Plane as Machine
An inclined plane analyzed as a simple machine that trades increased distance for decreased force.
Example: A loading ramp for trucks is 4 times as long as it is high, reducing required lifting force by a factor of 4.
Index of Refraction
A dimensionless number indicating how much light slows down and bends when entering a material from vacuum.
Example: Water has an index of refraction of 1.33, meaning light travels 1.33 times slower in water than in vacuum.
Inelastic Collisions
Collisions in which momentum is conserved but kinetic energy is not, with some energy converted to other forms.
Example: A car crash is an inelastic collision where kinetic energy transforms into sound, heat, and deformation.
Inertia
The tendency of an object to resist changes in its state of motion, proportional to its mass.
Example: A bowling ball has more inertia than a tennis ball, making it harder to start or stop moving.
Infrasound
Sound waves with frequencies below the range of human hearing, typically below 20 Hz.
Example: Elephants communicate using infrasound that can travel several kilometers.
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Insulators
Materials that resist the flow of electric charge due to tightly bound electrons.
<<<<<<< HEAD Example: Rubber coating on wires acts as an insulator, preventing electric current from escaping and causing shock hazards.
Kinematic Equations
A set of four equations relating displacement, velocity, acceleration, and time for constant acceleration motion.
Example: Using v² = v₀² + 2aΔx, an object starting at rest and accelerating at 2 m/s² travels 50 meters to reach 14.1 m/s.
Kinetic Energy
Energy possessed by an object due to its motion, equal to (1/2)mv².
Example: A 1000 kg car traveling at 20 m/s has 200,000 joules of kinetic energy that must be dissipated to stop.
Kinetic Friction
The friction force opposing motion between surfaces sliding relative to each other.
Example: Sliding a box across a floor experiences kinetic friction proportional to normal force, typically less than maximum static friction.
Law of Reflection
The principle that angle of incidence equals angle of reflection, both measured from the normal to the surface.
Example: Light hitting a mirror at 30° from the normal reflects at 30° on the opposite side of the normal.
Lens Equation
The relationship 1/f = 1/d₀ + 1/dᵢ connecting focal length, object distance, and image distance for thin lenses.
Example: A lens with focal length 10 cm forms an image 15 cm away when the object is placed 30 cm from the lens.
Lenses
Transparent optical elements with curved surfaces that refract light to form images.
Example: The human eye uses a flexible lens that changes shape to focus light from different distances onto the retina.
Lever
A rigid bar that rotates about a fixed pivot point, used to multiply force or distance.
Example: A 2-meter crowbar with fulcrum 20 cm from the load provides 10:1 mechanical advantage for lifting heavy objects.
Light Waves
Electromagnetic radiation in the visible spectrum, traveling at approximately 3 × 10⁸ m/s in vacuum.
Example: Light from the Sun takes about 8.3 minutes to reach Earth, traveling 150 million kilometers through space.
Linear Momentum
The product of an object's mass and velocity, a vector quantity representing quantity of motion.
Example: A 1000 kg car traveling at 20 m/s has 20,000 kg⋅m/s of momentum in the direction of motion.
Linear Motion
Motion along a straight line, described using one-dimensional kinematics.
Example: A train moving along straight tracks exhibits linear motion with position changing in only one direction.
Longitudinal Waves
Waves in which particle displacement is parallel to wave propagation direction.
Example: Sound waves are longitudinal; air molecules vibrate back and forth along the same line the sound travels.
Loudness
The subjective perception of sound intensity, related to but not identical with physical intensity.
Example: A 60 dB sound seems roughly twice as loud as 50 dB, though it represents 10 times more physical intensity.
Luminous Intensity
The power of light emitted per unit solid angle in a particular direction, measured in candelas.
Example: A standard candle emits approximately 1 candela of luminous intensity, the historical basis for the unit.
Magnification
The ratio of image size to object size, positive for upright images and negative for inverted images.
Example: A microscope with 400× magnification makes a 10 μm cell appear 4 mm in the eyepiece.
Mass vs Weight
The distinction between mass (quantity of matter) as an intrinsic property and weight (gravitational force) as location-dependent.
Example: An astronaut's 70 kg mass remains constant, but weight changes from 686 N on Earth to 114 N on the Moon.
Measurement
The process of determining a physical quantity's value by comparison with a standard unit.
Example: Measuring room length with a meter stick involves counting how many meter units fit along the dimension.
Mechanical Advantage
The ratio of output force to input force in a simple machine, indicating force multiplication capability.
Example: A pulley system with mechanical advantage 4 allows lifting 400 N with 100 N of input force.
Mechanical Energy
The sum of kinetic and potential energy in a system.
Example: A roller coaster at the top of a hill has maximum potential energy and minimum kinetic energy; total mechanical energy remains constant (ignoring friction).
Mechanical Waves
Disturbances that propagate through a material medium by particle interaction.
Example: Ocean waves are mechanical waves requiring water as a medium; they cannot travel through empty space.
Mirror Equation
The relationship 1/f = 1/d₀ + 1/dᵢ connecting focal length, object distance, and image distance for mirrors.
Example: A concave mirror with 15 cm focal length creates an image 30 cm behind when an object is placed 60 cm away.
Negative Charge
Electric charge carried by electrons, conventionally assigned a negative sign.
Example: An object with excess electrons has negative charge and attracts positively charged objects.
Net Force
The vector sum of all forces acting on an object, determining acceleration according to Newton's Second Law.
Example: A 10 N push right and 4 N friction left result in 6 N net force right, causing acceleration in that direction.
Newton's First Law
The principle that an object maintains constant velocity (including rest) unless acted upon by a net external force.
Example: A hockey puck on frictionless ice continues moving at constant velocity indefinitely without additional pushes.
Newton's Second Law
The principle that net force equals mass times acceleration, expressed as F_net = ma.
Example: Applying 20 N to a 5 kg object produces 4 m/s² acceleration in the force's direction.
Newton's Third Law
The principle that forces always occur in equal-magnitude, opposite-direction pairs acting on different objects.
Example: A rocket expels gas downward (action), while gas pushes rocket upward (reaction) with equal force.
Nodes and Antinodes
Points of zero amplitude (nodes) and maximum amplitude (antinodes) in standing wave patterns.
Example: A vibrating guitar string has nodes at both ends where it's fixed and antinodes at positions of maximum vibration.
Non-conservative Forces
Forces for which work done depends on path taken, typically dissipating mechanical energy.
Example: Friction is non-conservative; sliding an object in a circle wastes energy as heat, unlike conservative circular gravitational motion.
Normal Force
The perpendicular contact force a surface exerts on an object, preventing objects from passing through each other.
Example: A book resting on a table experiences an upward normal force equal in magnitude to its weight.
Optical Diffraction
The bending and spreading of light waves around obstacles or through apertures.
Example: Light passing through a narrow slit creates a diffraction pattern with a bright central band flanked by dimmer fringes.
Pendulum
An object suspended from a fixed point that swings back and forth under gravity's influence.
Example: A grandfather clock uses a pendulum with a period near 2 seconds to keep accurate time.
Period
The time required for one complete cycle of oscillation or revolution, measured in seconds.
Example: A pendulum taking 2 seconds per swing has a period of 2 s and frequency of 0.5 Hz.
Perfectly Inelastic Collisions
Collisions where objects stick together after impact, maximizing kinetic energy loss while conserving momentum.
Example: A freight car coupling with another stationary car demonstrates perfectly inelastic collision; they move together afterward with shared velocity.
Physical Pendulum
An extended rigid object that oscillates about a pivot point, with period depending on mass distribution.
Example: A swinging door is a physical pendulum with period determined by its rotational inertia about the hinges.
Pitch
The perceived frequency of sound, with higher frequencies producing higher pitch sensations.
Example: A violin's A string vibrates at 440 Hz, producing a higher pitch than a bass guitar's E string at 41 Hz.
Plane Mirrors
Flat reflective surfaces that produce virtual, upright, same-size images appearing to be the same distance behind the mirror as objects are in front.
Example: Your bathroom mirror reflection appears the same size as you and located an equal distance behind the mirror surface.
Polarization
The alignment of electromagnetic wave oscillations in a particular plane perpendicular to propagation direction.
Example: Polarized sunglasses block horizontally polarized glare from water surfaces while transmitting vertically polarized light.
Position-Time Graphs
Graphical representations showing how position changes over time, with slope indicating velocity.
Example: A position-time graph with positive constant slope represents motion at constant velocity in the positive direction.
Positive Charge
Electric charge carried by protons and certain ions, conventionally assigned a positive sign.
Example: An object with deficit electrons has positive charge and attracts negatively charged objects.
Potential Energy
Energy stored in a system due to position or configuration, capable of conversion to kinetic energy.
Example: Water held behind a dam possesses gravitational potential energy that converts to kinetic energy when released.
Power
The rate of energy transfer or work done per unit time, measured in watts (joules per second).
Example: Rubber coating on electrical wires acts as an insulator, preventing dangerous current flow.
Kinematic Equations
A set of four mathematical equations relating displacement, velocity, acceleration, and time for uniformly accelerated motion.
Example: Using kinematic equations, you can calculate how far a car travels while accelerating from rest to highway speed.
Kinetic Energy
Energy possessed by an object due to its motion, calculated as one-half mass times velocity squared.
Example: A 1000-kg car traveling at 20 m/s has 200,000 joules of kinetic energy.
Kinetic Friction
The friction force between surfaces in relative motion, typically less than static friction.
Example: Sliding a book across a table encounters kinetic friction that gradually slows it down.
Law of Reflection
The principle stating that the angle of incidence equals the angle of reflection when light bounces off a surface.
Example: When light hits a mirror at a 30-degree angle to the normal, it reflects at a 30-degree angle on the opposite side.
Lens Equation
A mathematical relationship connecting object distance, image distance, and focal length for lenses.
Example: Using the lens equation, you can calculate where a camera lens will focus light from a distant object.
Lenses
Transparent optical devices that refract light to form images by converging or diverging light rays.
Example: Eyeglasses use lenses to correct vision by properly focusing light onto the retina.
Lever
A rigid bar that rotates about a fixed pivot point (fulcrum), functioning as a simple machine to amplify force or distance.
Example: A crowbar is a lever that multiplies your input force to lift heavy objects.
Light Waves
Electromagnetic waves in the visible portion of the spectrum that can be detected by the human eye.
Example: Light waves from the sun travel through space to illuminate Earth.
Linear Momentum
The product of an object's mass and velocity, representing its quantity of motion.
Example: A 2-kg ball moving at 5 m/s has linear momentum of 10 kg·m/s.
Linear Motion
Motion along a straight line, described by position, velocity, and acceleration.
Example: A train traveling along a straight track exhibits linear motion.
Longitudinal Waves
Waves in which particle displacement is parallel to the direction of wave propagation.
Example: Sound waves are longitudinal, with air molecules vibrating back and forth in the same direction the sound travels.
Loudness
The subjective perception of sound intensity, influenced by both the amplitude of sound waves and the ear's sensitivity to different frequencies.
Example: A whisper has low loudness, while a jet engine has extremely high loudness.
Luminous Intensity
The amount of light energy emitted per unit time in a particular direction, measured in candelas.
Example: A typical candle has a luminous intensity of approximately one candela.
Magnification
The ratio of image size to object size produced by an optical system.
Example: A microscope with 400× magnification makes a cell appear 400 times larger than its actual size.
Mass vs Weight
The distinction between mass (the amount of matter in an object) and weight (the gravitational force acting on that mass).
Example: An astronaut's mass remains 70 kg on the Moon, but their weight is only about 115 newtons compared to 686 newtons on Earth.
Measurement
The process of quantitatively comparing a physical property to a standard unit.
Example: Using a ruler to determine that a pencil is 19 centimeters long is a measurement.
Mechanical Advantage
The ratio of output force to input force in a machine, indicating force multiplication.
Example: A pulley system with mechanical advantage of 4 allows you to lift 400 newtons using only 100 newtons of input force.
Mechanical Energy
The sum of kinetic energy and potential energy in a mechanical system.
Example: A swinging pendulum continuously exchanges mechanical energy between kinetic and potential forms.
Mechanical Waves
Waves that require a material medium to propagate, transferring energy through matter.
Example: Sound waves are mechanical waves that cannot travel through the vacuum of space.
Mirror Equation
A mathematical relationship connecting object distance, image distance, and focal length for mirrors.
Example: The mirror equation predicts where a concave mirror will form an image of your face.
Negative Charge
An excess of electrons relative to protons, conventionally represented as negative and repelling other negative charges.
Example: After rubbing a balloon on wool, the balloon gains a negative charge from extra electrons.
Net Force
The vector sum of all forces acting on an object, determining its acceleration according to Newton's Second Law.
Example: A 10-newton push to the right and a 3-newton push to the left result in a net force of 7 newtons to the right.
Newton's First Law
The principle stating that an object at rest stays at rest and an object in motion stays in motion with constant velocity unless acted upon by a net external force.
Example: A hockey puck sliding on ice continues moving in a straight line until friction or collision changes its motion.
Newton's Second Law
The principle stating that the net force on an object equals the product of its mass and acceleration (F = ma).
Example: Pushing a 5-kg cart with 20 newtons of net force produces an acceleration of 4 m/s².
Newton's Third Law
The principle stating that for every action force, there is an equal and opposite reaction force acting on a different object.
Example: When you jump, your legs push down on the ground, and the ground pushes up on you with equal force.
Nodes and Antinodes
Points in a standing wave where displacement is always zero (nodes) or maximum (antinodes).
Example: A vibrating guitar string has nodes at both ends where it's fixed and antinodes at points of maximum vibration.
Non-conservative Forces
Forces for which the work done depends on the path taken, typically converting mechanical energy to other forms.
Example: Friction is a non-conservative force that converts kinetic energy to thermal energy regardless of path.
Normal Force
The perpendicular contact force exerted by a surface on an object resting on it.
Example: A book on a table experiences an upward normal force from the table equal to the book's weight.
Optical Diffraction
The bending and spreading of light waves around obstacles or through openings.
Example: Light passing through a small slit creates a diffraction pattern with bright and dark bands on a screen.
Pendulum
A mass suspended from a fixed point that swings back and forth under the influence of gravity.
Example: A grandfather clock uses a pendulum to regulate its timekeeping through consistent oscillation periods.
Period
The time required for one complete oscillation or wave cycle, measured in seconds.
Example: A pendulum with a period of 2 seconds takes 2 seconds to swing forward and back to its starting position.
Perfectly Inelastic Collisions
Collisions where objects stick together after impact, resulting in maximum kinetic energy loss while conserving momentum.
Example: Two railroad cars coupling together during a collision is a perfectly inelastic collision.
Physical Pendulum
Any rigid body that oscillates about a fixed pivot point under gravitational torque.
Example: A baseball bat suspended from one end and allowed to swing acts as a physical pendulum.
Pitch
The subjective perception of sound frequency, with high frequencies perceived as high pitch and low frequencies as low pitch.
Example: A piccolo produces high-pitch sounds, while a tuba produces low-pitch sounds.
Plane Mirrors
Flat mirrors that produce virtual, upright images the same size as the object.
Example: A bathroom mirror is a plane mirror that shows your reflection at the same apparent distance behind the mirror as you are in front.
Polarization
The orientation of oscillations in a transverse wave, particularly the alignment of electric field oscillations in light.
Example: Polarized sunglasses block horizontally polarized light reflected from water, reducing glare.
Position-Time Graphs
Graphical representations showing how position varies over time, with time on the horizontal axis and position on the vertical axis.
Example: A position-time graph with a straight line indicates constant velocity motion.
Positive Charge
A deficit of electrons relative to protons, conventionally represented as positive and repelling other positive charges.
Example: A glass rod rubbed with silk acquires a positive charge by losing electrons.
Potential Energy
Stored energy in a system due to the position or configuration of objects.
Example: A compressed spring, an elevated mass, and separated opposite charges all have potential energy.
Power
The rate at which energy is transferred or work is performed, measured in watts (joules per second).
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Example: A 100-watt light bulb converts 100 joules of electrical energy to light and heat every second.
Precision vs Accuracy
<<<<<<< HEAD The distinction between measurement repeatability (precision) and closeness to true value (accuracy).
Example: A miscalibrated scale giving readings clustered around 105 g for a 100 g mass is precise but not accurate.
Prism
A transparent optical element with flat polished surfaces that refract light, often used to disperse white light into spectra.
Example: Newton used prisms to demonstrate that white sunlight contains all rainbow colors, separable by refraction.
Projectile Motion
Two-dimensional motion of objects launched into the air, with constant horizontal velocity and constant vertical acceleration.
Example: A basketball's arc from shooter to hoop follows projectile motion with parabolic trajectory.
Proportional Reasoning
The ability to understand and apply relationships where one quantity varies in direct or inverse proportion to another.
Example: Doubling force on an object doubles its acceleration (direct proportion), while doubling mass halves acceleration (inverse proportion).
Pulley as Machine
A wheel with a grooved rim used to change force direction or provide mechanical advantage in lifting systems.
Example: A fixed pulley changes force direction but provides no mechanical advantage; a movable pulley provides 2:1 mechanical advantage.
Pulley Systems
Combinations of fixed and movable pulleys that multiply force at the expense of increased rope distance.
Example: A 4-pulley system (2 fixed, 2 movable) provides 4:1 mechanical advantage for lifting heavy loads.
Ray Diagrams
Geometric constructions showing light ray paths to determine image formation by lenses and mirrors.
Example: Drawing three principal rays through a convex lens predicts image location and characteristics.
Real Images
Images formed by actual convergence of light rays, capable of projection onto screens.
Example: A movie projector creates real images on the screen as light rays from the film converge through the lens.
Reflection
The bouncing of waves off surfaces, with angle of incidence equal to angle of reflection.
Example: Sound echoes off a cliff face demonstrate reflection, with sound waves bouncing back to the source.
Refraction
The bending of waves when entering a medium with different wave speed, due to wavelength change.
Example: A straw in water appears bent at the surface due to light refraction between air and water.
Relative Velocity
The velocity of one object measured with respect to another moving object's reference frame.
Example: Two cars traveling 60 mph and 50 mph in the same direction have relative velocity of 10 mph.
Resonance
The dramatic amplitude increase when driving frequency matches a system's natural frequency.
Example: Pushing a swing at its natural frequency causes amplitude to build up, demonstrating resonance.
Restoring Force
A force that always acts to return a displaced object toward its equilibrium position.
Example: A stretched spring exerts a restoring force pulling back toward its natural length, proportional to displacement.
Rocket Propulsion
Motion achieved by expelling mass in one direction, producing thrust in the opposite direction via Newton's Third Law.
Example: Rocket engines burn fuel to expel hot gases downward at high velocity, propelling the rocket upward.
Rolling Motion
Combined rotational and translational motion where contact point has zero instantaneous velocity.
Example: A wheel rolling without slipping on a road demonstrates rolling motion, with bottom point momentarily at rest.
Rotational Inertia
The measure of an object's resistance to changes in rotational motion, depending on mass distribution relative to rotation axis.
Example: A figure skater has high rotational inertia with arms extended and low inertia with arms pulled in.
Rotational Kinetic Energy
Energy possessed by a rotating object, equal to (1/2)Iω², where I is rotational inertia and ω is angular velocity.
Example: A spinning flywheel stores rotational kinetic energy used to smooth engine power delivery.
Rotational Kinematics
The description of rotational motion using angular displacement, velocity, and acceleration without considering forces.
Example: A wheel accelerating from rest at 2 rad/s² reaches 20 rad/s angular velocity after 10 seconds.
Scalars
Physical quantities characterized completely by magnitude alone, without directional component.
Example: Temperature, mass, speed, and energy are scalars; 50 kg and 25°C require no direction specification.
The distinction between the reproducibility of measurements (precision) and their closeness to the true value (accuracy).
Example: A poorly calibrated scale might give precise but inaccurate readings that cluster around the wrong value.
Prism
A transparent optical element with flat, polished surfaces that refract light, often used to disperse white light into colors.
Example: A triangular glass prism separates sunlight into a rainbow of colors.
Projectile Motion
Two-dimensional motion of an object under the influence of gravity alone, combining horizontal uniform motion with vertical accelerated motion.
Example: A basketball shot follows projectile motion, with a parabolic path determined by its initial velocity and gravity.
Proportional Reasoning
The mathematical skill of understanding and working with relationships where one quantity varies directly or inversely with another.
Example: Understanding that doubling the mass of an object doubles its weight demonstrates proportional reasoning.
Pulley as Machine
A pulley system analyzed as a simple machine that can change force direction and provide mechanical advantage.
Example: A crane uses multiple pulleys to lift heavy loads with less input force.
Pulley Systems
Arrangements of wheels and ropes that redirect forces and provide mechanical advantage for lifting loads.
Example: A flagpole uses a pulley system to raise and lower the flag easily.
Ray Diagrams
Schematic drawings using light rays to trace image formation by lenses and mirrors.
Example: A ray diagram for a convex lens shows how parallel rays converge at the focal point.
Real Images
Images formed where light rays actually converge, capable of being projected onto a screen.
Example: A movie projector creates a real image on the screen where light physically arrives.
Reflection
The bouncing of light or other waves off a surface, following the law of reflection.
Example: Seeing your image in a mirror is due to reflection of light from your face.
Refraction
The bending of waves as they pass from one medium to another due to a change in wave speed.
Example: A straw appears bent when placed in a glass of water due to refraction of light at the water-air boundary.
Relative Velocity
The velocity of one object as observed from the reference frame of another moving object.
Example: Two cars traveling 60 mph in the same direction have a relative velocity of zero, appearing stationary to each other.
Resonance
The dramatic increase in amplitude when a system is driven at its natural frequency.
Example: Pushing a child on a swing at the right timing creates resonance, building up a large amplitude with minimal effort.
Restoring Force
A force that acts to return a displaced object to its equilibrium position.
Example: When you stretch a spring, the restoring force pulls it back toward its natural length.
Rocket Propulsion
Locomotion achieved by expelling mass in one direction to generate thrust in the opposite direction, demonstrating Newton's Third Law.
Example: A rocket expels hot gas downward, and by Newton's Third Law, the gas pushes the rocket upward.
Rolling Motion
Combined rotational and translational motion where an object rolls without slipping along a surface.
Example: A bicycle wheel exhibits rolling motion, simultaneously rotating about its axis and translating forward.
Rotational Inertia
The resistance of a rotating object to changes in its rotational motion, depending on both mass and mass distribution.
Example: A figure skater has less rotational inertia with arms pulled in than with arms extended, explaining faster spinning.
Rotational Kinetic Energy
Energy associated with rotational motion, equal to one-half the rotational inertia times angular velocity squared.
Example: A spinning flywheel stores rotational kinetic energy that can be released to do work.
Rotational Kinematics
The description of rotational motion using angular displacement, angular velocity, and angular acceleration.
Example: Analyzing a spinning wheel's motion using rotational kinematics reveals how its angular velocity changes over time.
Scalars
Physical quantities that have magnitude but no direction.
Example: Temperature, mass, time, and speed are all scalars because they need only a number and unit to be specified.
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Scientific Method
A systematic approach to investigating phenomena through observation, hypothesis formation, experimentation, and conclusion.
<<<<<<< HEAD Example: Testing whether fertilizer increases plant growth involves controlled experiments comparing treated and untreated groups.
Scientific Notation
A standardized format expressing numbers as a coefficient between 1 and 10 multiplied by a power of ten.
Example: The speed of light 300,000,000 m/s is written as 3.0 × 10⁸ m/s in scientific notation.
Example: Testing whether fertilizer affects plant growth involves the scientific method: forming a hypothesis, designing controlled experiments, and analyzing results.
Scientific Notation
A method of expressing very large or very small numbers as a product of a number between 1 and 10 and a power of 10.
Example: The speed of light, 300,000,000 m/s, is written as 3.0 × 10⁸ m/s in scientific notation.
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Semiconductors
Materials with electrical conductivity between conductors and insulators, controllable by temperature or impurities.
<<<<<<< HEAD Example: Silicon semiconductors in computer chips can switch between conducting and insulating states, enabling digital logic.
Shock Waves
Disturbances created when a source moves faster than wave propagation speed in a medium.
Example: A supersonic jet creates shock waves heard as sonic booms when traveling faster than sound.
SI Units
The International System of Units providing standardized base units for physical quantities.
Example: The seven SI base units include meter (length), kilogram (mass), second (time), ampere (current), kelvin (temperature), mole (amount), and candela (luminous intensity).
Significant Figures
The number of digits in a measurement that carry meaningful information about precision.
Example: Measuring 15.20 cm (four significant figures) indicates greater precision than 15 cm (two significant figures).
Simple Harmonic Motion
Periodic motion where restoring force is proportional to displacement, producing sinusoidal position-time behavior.
Example: A mass on a spring oscillates with simple harmonic motion, with position described by x = A cos(ωt).
Simple Machines
Basic mechanical devices that multiply force or change its direction, including lever, wheel and axle, pulley, inclined plane, wedge, and screw.
Example: A bottle opener is a lever-class simple machine that multiplies applied force to remove bottle caps.
Simple Pendulum
An idealized pendulum consisting of a point mass suspended by a massless string, exhibiting simple harmonic motion for small angles.
Example: A small weight on a long string approximates a simple pendulum with period depending on length and gravity.
Single Slit Diffraction
The spreading of light into a pattern of central bright band and side fringes after passing through a narrow opening.
Example: Laser light through a thin slit projects a pattern with a wide central band and progressively dimmer side bands.
Snell's Law
The principle that n₁sin(θ₁) = n₂sin(θ₂) relates angles and indices of refraction at a boundary between media.
Example: Light entering water from air at 45° refracts to about 32° because water's higher index of refraction.
Example: Silicon semiconductors in computer chips can be switched between conducting and insulating states to process information.
Shock Waves
Pressure waves formed when an object travels faster than the wave speed in that medium, creating a cone-shaped disturbance.
Example: A supersonic jet creates a shock wave heard on the ground as a sonic boom.
SI Units
The International System of Units, a standardized metric system using base units like meters, kilograms, and seconds.
Example: Scientists worldwide use SI units, measuring length in meters rather than feet or yards.
Significant Figures
The digits in a measurement that carry meaningful information about its precision.
Example: Measuring 12.50 cm has four significant figures, indicating precision to the hundredths place.
Simple Harmonic Motion
Oscillatory motion where the restoring force is directly proportional to displacement from equilibrium.
Example: A mass bobbing on a spring exhibits simple harmonic motion with sinusoidal position variation over time.
Simple Machines
Basic mechanical devices that change the magnitude or direction of forces, including levers, pulleys, inclined planes, wedges, screws, and wheels-and-axles.
Example: A screwdriver is a simple machine combining a wheel and axle to multiply torque.
Simple Pendulum
An idealized pendulum consisting of a point mass suspended by a massless string, swinging under gravity.
Example: A small dense bob on a long thin string approximates a simple pendulum for physics experiments.
Single Slit Diffraction
The spreading and interference pattern created when light passes through a single narrow opening.
Example: Laser light shining through a thin slit creates a single slit diffraction pattern with a bright central band and dimmer side bands.
Snell's Law
The mathematical relationship describing how light bends when crossing a boundary between materials with different refractive indices.
Example: Snell's Law explains why a pencil appears bent at the water surface in a glass.
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Sound Intensity
The power per unit area carried by sound waves, measured in watts per square meter.
<<<<<<< HEAD Example: Doubling distance from a point sound source reduces intensity to one-quarter, following inverse square law.
Sound Waves
Longitudinal mechanical waves that propagate through air or other media as pressure variations.
Example: Speaking creates sound waves as vocal cord vibrations compress and rarefy air molecules at frequencies from 85 to 255 Hz.
Speed
A scalar quantity representing the rate of distance covered per unit time, always positive or zero.
Example: A car's speedometer reading 60 mph indicates speed; it doesn't specify direction of travel.
Speed of Light
The constant speed of electromagnetic radiation in vacuum, approximately 3.0 × 10⁸ m/s.
Example: Light takes 1.28 seconds to travel from Earth to the Moon, covering 384,400 kilometers.
Speed of Sound
The propagation speed of sound waves through a medium, approximately 343 m/s in air at room temperature.
Example: Thunder heard 3 seconds after seeing lightning indicates the storm is about 1 kilometer away (343 m/s × 3 s ≈ 1000 m).
Spherical Mirrors
Mirrors with surfaces forming part of a sphere, capable of focusing light (concave) or diverging it (convex).
Example: Telescope mirrors use large concave spherical or parabolic surfaces to collect and focus light from distant objects.
Spring Constant
The measure of spring stiffness, representing force required per unit extension, measured in newtons per meter.
Example: A spring with k = 200 N/m requires 20 N to stretch 0.1 m and stores 1 joule of elastic potential energy.
Standing Waves
Stationary wave patterns formed by interference of waves traveling in opposite directions with same frequency.
Example: A guitar string vibrates in standing wave patterns with nodes at ends and antinodes where amplitude is maximum.
Static Equilibrium
A state where an object remains at rest because both net force and net torque equal zero.
Example: A ladder leaning against a wall is in static equilibrium when forces and torques balance, preventing sliding or tipping.
Static Friction
The friction force that prevents motion between surfaces at rest relative to each other, up to a maximum value.
Example: A book on an inclined plane remains stationary as static friction balances the downslope component of weight.
Superconductors
Materials that exhibit zero electrical resistance below a critical temperature, allowing persistent currents.
Example: Superconducting magnets in MRI machines maintain intense magnetic fields with negligible power consumption.
Superposition Principle
The principle that net displacement at any point equals the sum of individual wave displacements at that point.
Example: When two water waves meet, the water surface height is the sum of heights from each wave separately.
Tension
The pulling force transmitted through a string, rope, cable, or chain when pulled from opposite ends.
Example: Hanging a 10 kg mass from a rope creates 98 N tension throughout the rope (assuming massless rope).
Thin Lens Formula
An alternative form of the lens equation: 1/f = (n-1)(1/R₁ - 1/R₂), relating focal length to refractive index and surface curvatures.
Example: A glass lens (n = 1.5) with surfaces of radii 10 cm and 15 cm has a calculable focal length from the thin lens formula.
Total Internal Reflection
The complete reflection of light at a boundary when light travels from denser to less dense medium beyond critical angle.
Example: Fiber optic cables use total internal reflection to transmit light signals over long distances with minimal loss.
Torque
The rotational effect of a force, equal to the product of force and perpendicular distance from rotation axis.
Example: Applying 100 N at the end of a 0.3 m wrench produces 30 N⋅m of torque to tighten a bolt.
Transverse Waves
Waves in which particle displacement is perpendicular to wave propagation direction.
Example: Light waves and waves on a string are transverse; oscillations occur perpendicular to the travel direction.
Trigonometry for Physics
The application of sine, cosine, and tangent functions to analyze vector components and angular relationships.
Example: A 100 N force at 30° has horizontal component 100cos(30°) = 86.6 N and vertical component 100sin(30°) = 50 N.
2D Collisions
Collisions where objects approach from non-parallel directions, requiring vector analysis in two dimensions.
Example: Pool balls colliding at an angle scatter in different directions with momentum conserved as vectors in both x and y directions.
Ultrasound
Sound waves with frequencies above the upper limit of human hearing (approximately 20,000 Hz).
Example: Medical ultrasound uses frequencies above 1 MHz to create images of internal body structures.
Uniform Motion
Motion at constant velocity, with zero acceleration and equal displacements in equal time intervals.
Example: A car on cruise control traveling at steady 60 mph on straight highway exhibits uniform motion.
Uniformly Accelerated Motion
Motion with constant non-zero acceleration, described by kinematic equations.
Example: A ball dropped from rest undergoes uniformly accelerated motion at 9.8 m/s² downward.
Unit Conversion
The process of changing measurement values from one unit system to another using conversion factors.
Example: Converting 5 km to meters: 5 km × 1000 m/km = 5000 m.
Vector Addition
The process of combining vectors using head-to-tail method or component addition to find resultant vector.
Example: Walking 3 m east then 4 m north results in a resultant displacement of 5 m northeast (3-4-5 triangle).
Vector Components
The projections of a vector along perpendicular coordinate axes, typically x and y directions.
Example: A 100 m displacement at 37° above horizontal has components 80 m horizontal and 60 m vertical.
Vector Subtraction
The process of finding the difference between vectors by adding the negative of the second vector.
Example: Velocity change Δv = v_final - v_initial involves subtracting initial from final velocity vectors.
Vectors
Physical quantities characterized by both magnitude and direction, represented by arrows.
Example: Displacement, velocity, force, and momentum are vectors; a velocity of 50 m/s north specifies both speed and direction.
Velocity
A vector quantity representing the rate of displacement change with respect to time, including direction.
Example: A car traveling 60 mph west has velocity of -60 mph if east is defined as positive direction.
Velocity-Time Graphs
Graphical representations showing how velocity changes over time, with slope indicating acceleration and area representing displacement.
Example: A horizontal line on a velocity-time graph indicates constant velocity; a sloped line indicates acceleration.
Virtual Images
Images formed where light rays appear to diverge from, but don't actually pass through, unable to project onto screens.
Example: Your reflection in a plane mirror is a virtual image appearing behind the mirror where light rays don't actually converge.
Visible Spectrum
The portion of electromagnetic spectrum detectable by human eyes, approximately 400-700 nanometers wavelength.
Example: The visible spectrum ranges from violet (shortest wavelength, ~400 nm) through blue, green, yellow, orange, to red (longest, ~700 nm).
Voltage
The electric potential difference between two points, measuring energy per unit charge, expressed in volts.
Example: A 9-volt battery provides 9 joules of energy to each coulomb of charge flowing through it.
Wave Diffraction
The bending and spreading of waves around obstacles or through openings.
Example: Sound waves diffract around corners, allowing you to hear someone speaking from another room.
Wave Frequency
The number of wave cycles passing a point per unit time, measured in hertz.
Example: A wave with 5 crests passing per second has a frequency of 5 Hz.
Wave Interference
The combination of two or more waves occupying the same space simultaneously, following superposition principle.
Example: Ripples from two stones dropped in water create interference patterns where wave crests overlap.
Wave Period
The time required for one complete wave cycle to pass a fixed point, equal to 1/frequency.
Example: A wave with frequency 2 Hz has a period of 0.5 seconds per cycle.
Wave Properties
Characteristics describing waves including wavelength, frequency, amplitude, speed, and direction.
Example: Ocean waves are characterized by properties like 2-meter amplitude, 10-second period, and 0.1 Hz frequency.
Wave Reflection
The bouncing back of waves when encountering a boundary or obstacle.
Example: Ocean waves reflect off seawalls, creating complex interference patterns near coastal structures.
Wave Refraction
The bending of waves when entering a medium where wave speed changes.
Example: Ocean waves approaching shore at an angle refract to become more parallel to the beach as they slow in shallow water.
Wave Speed
The rate at which wave disturbances propagate through a medium, equal to wavelength times frequency.
Example: A wave with 2-meter wavelength and 0.5 Hz frequency travels at 1 m/s (v = λf = 2 m × 0.5 Hz).
Wavelength
The distance between consecutive corresponding points on a wave, such as crest to crest.
Example: Red light has wavelength around 700 nm, while blue light has shorter wavelength near 400 nm.
Weight
The gravitational force acting on an object's mass, equal to mg near Earth's surface.
Example: A 5 kg object has weight of 49 N on Earth (5 kg × 9.8 m/s²) but only 8.1 N on the Moon.
Work
The energy transfer accomplished by a force acting through a displacement, equal to force times parallel displacement.
Example: Lifting a 10 kg box 2 meters high requires 196 joules of work against gravity (W = mgh = 10 × 9.8 × 2).
Work by Constant Force
Work calculated as the product of constant force magnitude, displacement, and cosine of angle between them.
Example: Pushing a 50 N force through 10 m displacement in the force direction performs 500 joules of work.
Work by Variable Force
Work calculated by integrating force over displacement when force changes with position.
Example: Compressing a spring requires variable force (F = kx); work equals the area under the force-displacement curve, or (1/2)kx².
Work-Energy Theorem
The principle that net work done on an object equals its change in kinetic energy.
Example: A 20 N force pushing a 2 kg object through 5 m increases its kinetic energy by 100 joules.
Young's Double Slit
An experiment demonstrating light interference by passing light through two narrow parallel slits, creating alternating bright and dark bands.
Example: Young's double slit experiment proved light's wave nature by showing interference patterns impossible for particles.
Example: Standing near a speaker produces higher sound intensity than standing far away, even though the power output is the same.
Sound Waves
Longitudinal mechanical waves that propagate through a medium as compressions and rarefactions.
Example: When you speak, sound waves travel through air to reach a listener's ear.
Speed
A scalar quantity measuring the rate of distance covered, calculated as distance divided by time.
Example: A car traveling 100 kilometers in 2 hours has a speed of 50 km/h.
Speed of Light
The constant speed at which electromagnetic radiation travels in vacuum, approximately 3.0 × 10⁸ meters per second.
Example: Light from the sun takes about 8 minutes to reach Earth, traveling at the speed of light through space.
Speed of Sound
The rate at which sound waves propagate through a medium, varying with the medium's properties and temperature.
Example: At room temperature, sound travels through air at approximately 343 meters per second.
Spherical Mirrors
Curved mirrors with surfaces that form part of a sphere, either concave or convex.
Example: Automobile side mirrors are spherical mirrors designed to provide a wide field of view.
Spring Constant
A measure of spring stiffness, equal to the force required per unit displacement, measured in newtons per meter.
Example: A spring with spring constant 100 N/m requires 50 newtons to stretch it 0.5 meters.
Standing Waves
Wave patterns that appear stationary, formed by interference between waves traveling in opposite directions.
Example: A guitar string vibrates in standing wave patterns with nodes at both ends.
Static Equilibrium
A state where an object remains at rest because all forces and torques acting on it are balanced.
Example: A ladder leaning against a wall is in static equilibrium when properly positioned.
Static Friction
The friction force between surfaces at rest relative to each other, preventing motion up to a maximum value.
Example: Static friction keeps a parked car stationary on a hill until the slope becomes too steep.
Superconductors
Materials that exhibit zero electrical resistance when cooled below a critical temperature.
Example: Superconducting magnets in MRI machines conduct electricity without energy loss, creating powerful magnetic fields.
Superposition Principle
The principle stating that when two or more waves overlap, the resultant displacement is the sum of individual displacements.
Example: When two water waves meet, they combine according to the superposition principle, creating regions of larger and smaller amplitude.
Tension
The pulling force transmitted through a string, rope, cable, or similar object when forces are applied at both ends.
Example: The tension in a rope during a tug-of-war equals the pulling force applied at each end.
Thin Lens Formula
An equation relating object distance, image distance, and focal length for thin lenses: 1/f = 1/do + 1/di.
Example: The thin lens formula calculates that an object 30 cm from a lens with 10 cm focal length creates an image 15 cm from the lens.
Total Internal Reflection
The complete reflection of light at the boundary between a denser and less dense medium when the angle of incidence exceeds the critical angle.
Example: Diamonds sparkle brilliantly because their high refractive index causes total internal reflection, trapping and reflecting light internally.
Torque
The rotational analog of force, equal to the product of force and perpendicular distance from the rotation axis.
Example: Using a longer wrench increases the distance from the bolt, multiplying the torque you can apply.
Transverse Waves
Waves in which particle displacement is perpendicular to the direction of wave propagation.
Example: Light waves and waves on a rope are transverse, with oscillations perpendicular to the wave's travel direction.
Trigonometry for Physics
The application of sine, cosine, and tangent functions to resolve vectors and analyze angular relationships in physical problems.
Example: Calculating the vertical component of a force applied at 30 degrees requires using sine or cosine from trigonometry.
2D Collisions
Collisions occurring in a plane where momentum must be conserved in both x and y directions independently.
Example: A billiard ball hitting another at an angle demonstrates a 2D collision with momentum vectors changing in two dimensions.
Ultrasound
Sound waves with frequencies above the range of human hearing, typically above 20,000 Hz.
Example: Medical ultrasound imaging uses high-frequency sound waves to visualize internal body structures.
Uniform Motion
Motion at constant velocity with zero acceleration.
Example: A car using cruise control on a straight highway maintains uniform motion.
Uniformly Accelerated Motion
Motion with constant acceleration, where velocity changes by equal amounts in equal time intervals.
Example: A ball dropped from rest undergoes uniformly accelerated motion with acceleration equal to g.
Unit Conversion
The process of changing a measurement from one unit system to another using conversion factors.
Example: Converting 50 miles per hour to meters per second requires unit conversion: 50 mi/h = 22.4 m/s.
Vector Addition
The process of combining two or more vectors to find their resultant using geometric or component methods.
Example: Walking 3 meters east then 4 meters north combines through vector addition to give a 5-meter northeast displacement.
Vector Components
The projections of a vector along coordinate axes, allowing two-dimensional vectors to be expressed as separate perpendicular parts.
Example: A force of 10 newtons at 30° above horizontal has components of 8.66 N horizontal and 5 N vertical.
Vector Subtraction
The process of finding the difference between vectors by adding the negative of the second vector to the first.
Example: Finding relative velocity requires vector subtraction of one object's velocity from another's.
Vectors
Physical quantities that have both magnitude and direction, represented by arrows in diagrams.
Example: Displacement, velocity, acceleration, and force are all vectors requiring both magnitude and direction for complete specification.
Velocity
A vector quantity describing the rate of change of position, including both speed and direction.
Example: A car traveling 60 km/h northward has a velocity that specifies both how fast and which direction it's moving.
Velocity-Time Graphs
Graphical representations showing how velocity varies over time, with time on the horizontal axis and velocity on the vertical axis.
Example: The area under a velocity-time graph represents the displacement traveled during that time interval.
Virtual Images
Images formed where light rays appear to diverge from, but do not actually pass through, unable to be projected onto a screen.
Example: The image you see in a plane mirror is a virtual image appearing behind the mirror surface.
Visible Spectrum
The portion of the electromagnetic spectrum detectable by human eyes, ranging from approximately 400 nm (violet) to 700 nm (red).
Example: A rainbow displays the visible spectrum as water droplets separate sunlight into its component wavelengths.
Voltage
The electric potential difference between two points, representing energy per unit charge, measured in volts.
Example: A 12-volt battery provides 12 joules of energy per coulomb of charge that flows through a circuit.
Wave Diffraction
The bending and spreading of waves as they pass through openings or around obstacles.
Example: You can hear someone talking around a corner because sound waves undergo diffraction, bending around the obstacle.
Wave Frequency
The number of wave cycles passing a fixed point per unit time, measured in hertz.
Example: FM radio waves with frequency 100 MHz have 100 million wave cycles passing by each second.
Wave Interference
The combination of two or more waves occupying the same space, producing a resultant wave.
Example: Ripples from two stones dropped in water demonstrate wave interference, creating complex patterns where they meet.
Wave Period
The time required for one complete wave cycle to pass a fixed point, equal to the reciprocal of frequency.
Example: Ocean waves with a 10-second period have a new crest arrive every 10 seconds.
Wave Properties
Characteristics that describe waves, including wavelength, frequency, amplitude, speed, and phase.
Example: Understanding wave properties allows us to distinguish between different types of electromagnetic radiation.
Wave Reflection
The bouncing back of waves when they encounter a boundary or obstacle.
Example: Echoes are caused by wave reflection of sound off distant surfaces like canyon walls.
Wave Refraction
The change in direction of waves as they pass from one medium to another at an angle, caused by a change in wave speed.
Example: Ocean waves bend as they approach shore due to wave refraction caused by decreasing water depth.
Wave Speed
The rate at which a wave disturbance propagates through a medium, equal to wavelength times frequency.
Example: Radio waves travel at the speed of light, approximately 300,000 kilometers per second through vacuum.
Wavelength
The spatial distance between two consecutive corresponding points on a wave, such as crest to crest or trough to trough.
Example: Red light has wavelengths around 700 nanometers, nearly twice the wavelength of violet light at 400 nanometers.
Weight
The gravitational force acting on an object, equal to mass times gravitational acceleration.
Example: A 10-kilogram object on Earth has a weight of approximately 98 newtons.
Work
The transfer of energy that occurs when a force acts on an object through a displacement in the direction of the force.
Example: Lifting a 20-kg box 1.5 meters requires 294 joules of work against gravity.
Work by Constant Force
Work calculated as the product of force magnitude, displacement magnitude, and the cosine of the angle between them.
Example: Pushing a lawn mower with 50 newtons of force over 20 meters requires 1000 joules of work.
Work by Variable Force
Work calculated by integrating force over displacement when the force magnitude changes during motion.
Example: Compressing a spring requires work by variable force because the spring force increases with compression.
Work-Energy Theorem
The principle stating that the net work done on an object equals its change in kinetic energy.
Example: The work-energy theorem explains that when you apply brakes, negative work reduces a car's kinetic energy to zero.
Young's Double Slit
An experiment demonstrating light's wave nature by passing light through two closely spaced slits, producing an interference pattern.
Example: Young's double slit experiment shows alternating bright and dark bands proving light behaves as a wave.
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