How much work must be done to accelerate an 8.5×10^5 kg train from a) 10m/s to 15m/s b) 15m/s to 20m/s and c) to an initial stop of 20m/s

In the sport of parasailing, a person is attached to a rope being pulled by a boat while hanging from a parachute-like sail. a rider is towed at a constant speed by a rope that is at an angle of 15 ∘ from horizontal. the tension in the rope is 1900 n. the force of the sail on the rider is 30∘ from horizontal. what is the weight of the rider? express your answer with the appropriate units.

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity

Chemical energy is a form of energy. a. heat b. kinetic c. potential d. electromagnetic