Physlet Illustration: Conservation of Angular Momentum

 

 

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A red disk is dropped onto a rotating yellow disk which has a mass of 20 kg as shown in the animation (position is measured in meters and time is in seconds). What is the mass of the red disk?

Hints

  1. Measure the radii of two disks and the angular speed before and after the collision.
  2. What is the angular momentum before the collision?
  3. What is the angular momentum after the collision?  Is it equal to the value before?

Reference

See Walker, Section 11-2

Illustration written by Aaron Titus and Modified by Chuck Niederriter