Conceptual Example 14 provides useful background for this problem.A playground carousel is free to rotate about its center onfrictionless bearings, and air resistance is negligible. Thecarousel itself (without riders) has a moment of inertia of 113kg·m2. When one person is standing at a distanceof 1.49 m from the center, the carousel has an angular velocity of0.649 rad/s. However, as this person moves inward to a pointlocated 0.716 m from the center, the angular velocity increases to0.768 rad/s. What is the person's mass?
Explanation / Answer
Step I : Find initial angular momentum of thesystem L1 = ( I + mx2) 1 where x =1.49 m Step II : Find final angular momentum of thesystem L2 = ( I + my2 ) 2 where y = 0.716 m Step III ; Apply law of conservation ofmomentum. L1 = L2 Solve and get the result. Use I = 113 Solve and get the result. Use I = 113