Child on a Merry-Go-Round: Calculating Angular Velocity After Moving Inward

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AI Thread Summary
To solve the problem of a child moving inward on a merry-go-round, the conservation of angular momentum is key, as no external torque is acting on the system. Initially, the child is 2m from the center, and the merry-go-round spins at 30 RPM. When the child moves to 1.5m, the angular momentum before and after must remain constant. The calculation involves using the formula for angular momentum and adjusting for the change in radius. The final angular velocity can be determined by equating the initial and final angular momentum values.
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Homework Statement


A child with a mass of 40kg is sitting 2m from the center of a merry go round. He moves inward to a point 1.5m from the center. If the merry go round was originally spinning at 30rpm's, how fast is it spinning after the child moves inward?


Homework Equations





The Attempt at a Solution

 
Physics news on Phys.org
Welcome to PF.

How would you think to approach the problem?
 
I really do not have a clue. i can't seem to find which formula I need to use.
 
What is the initial state?
What is the final state?
The preservation of what quantities holds here?
 
Hint: No net external torque acts on the system.
 

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