A merry-go-round in the park has a radius of 1.8 m and a rotational inertia of 900 kg·m². A child pushes the merry -go-round with a constant force of 80 N applied at the edge and parallel to the edge. A frictional torque of 12 N·m acts at the axle of the merry-go-round.
a. What is the net torque acting on the merry-go-round about its axle?
b. What is the rotational acceleration of the merry-goround?
c. At this rate, what will the rotational velocity of the merry-go-round be after 15 s if it starts from rest?
d. What is the rotational acceleration of the merry-goround if the child stops pushing after 15 s? How long will it take for the merry-go-round to stop turning?