A father exerts a 2.51 102 N force to pull a sled with his daughter on it (combined mass of 77.9 kg) across a horizontal surface. The rope with which he pulls the sled makes an angle of 20.0° with the horizontal. The coefficient of kinetic friction is 0.200, and the sled moves a distance of 7.41 m.
(a) Find the work done by the father.
(b) Find the work done by the friction force.
(c) Find the total work done by all the forces.