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Rolling Motion Velocity Vectors

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About This MicroSim

This simulation shows velocity vectors at different points on a rolling wheel. Each point has velocity from both the wheel's translation (v_cm) and its rotation (ωr).

Key Observations

  • Bottom point: v = 0 (instantaneously stationary!)
  • Center point: v = v_cm (pure translation)
  • Top point: v = 2v_cm (translation + rotation add)
  • Side points: Have components in both directions

Rolling Without Slipping

The constraint v_cm = rω ensures the bottom point is stationary. This is what allows static friction to enable rolling without slipping.

Controls

  • Speed Slider: Adjust the center of mass velocity
  • Freeze Frame: Pause to examine velocity vectors
  • Show vectors: Toggle velocity vector display
  • Show trace paths: See the cycloid path of rim points!

Lesson Plan

Discussion Questions

  1. Why is the bottom point stationary?
  2. What happens if v_cm ≠ rω?
  3. What shape does the top point trace? (Hint: cycloid)