일반물리학 1 — Potential Energy and Conservation of Energy: Problem 45

45 A loaded truck of mass 3000 kg moves on a level road at a constant speed of 6.000 m/s. The frictional force on the truck from the road is 1000 N. Assume that air drag is negligible. (a) How much work is done by the truck engine in 10.00 min? (b) After 10.00 min, the truck enters a hilly region whose inclination is 30° and continues to move with the same speed for another 10.00 min. What is the total work done by the engine during that period against the gravitational force and the frictional force? (c) What is the total work done by the engine in the full 20 min?