A force of constant magnitude pushes a box up a vertical surface, as shown in the gure. The box moves at a constant speed. If the mass of the box is 4.5 kg, it is pushed 2.5 m vertically upward, the coefficient of friction is 0.35, and the angle 0 is 30.0, determine the following. (a) the work done (in J) on the box by F H (b) the work done (in J) on the box by the force of gravity J U (c) the work done (in J) on the box by the normal force J U (cl) the increase in gravitational potential energy (in J) of the system of the box and earth as the box moves up the wall J U