The boy a rotating merry-go-round, his mass is 40 kg, he stands at a distance 0.90 m from the axis of a rotation. The merry-go-round can be approximated as a uniform solid disk with a mass of 450 kg and a radius of 2.10 m. Calculate the moment of inertia of this system.

the answer is a. at the equator

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.

the maxium height is 34m/s