$4$

Woohoo!

Let's keep bringing class stuff! Your friend sits on this spinning stool that can rotate freely about its symmetry axis, and you give them a push so they start rotating with two weights on their hands close to their body as shown. We already saw that when they extend their arms and bring the weights far from their body, the angular speed of the system decreases. What happens to the total kinetic energy of the system?

A$.$ It increases

B$.$ It decreases

C$.$ It stays the same

D$.$ There is not enough information to know for sure

A

B

C