A box having a mass of 0.2 kg is dragged across a horizontal floor by means of a rope tied on the front of it. The coefficient of sliding friction
between the box and the floor is 0.2. If the angle between the rope and
the floor is 15º, what force must be exerted on the rope to move the box
at constant speed.

Aplayground merry-go-round has a radius of 4.6 m and a moment of inertia of 200 kg-m2 and turns with negligible friction about a vertical axle through its center. a child applies a 26.0 n force tangentially to the edge of the merry-go-round for 15.0 seconds. if the merry-go-round is initially at rest, how much work did the child do on the merry-go-round?