You want to accelerate a small merry-go-round from rest to the rotational speed of one-fourth of a revolution per second by pushing tangentially on it. Suppose that the merry-go-round is a disk having a mass of around 230 kg and a radius of around 1.60 m. Avoid friction, how hard do you have to push tangentially to achieve this in 7.00 s? (Employ energy methods and suppose a constant push on your part.)