A teenager pushes tangentially on a small hand-driven merry-go-round and is able to accelerate it from rest to a frequency of 17 in 9.1 . Assume the merry-go-round is a uniform disk of radius 2.5 and has a mass of 770 , and two children (each with a mass of 24 ) sit opposite each other on the edge. a) Calculate the torque required to produce the acceleration, neglecting frictional torque. b)What force is required at the edge?