Question

A car of mass 1500 kg has a constant speed of 40 m/s when travelling up a hill
inclined at sin-1 (1/15) to the horizontal with the engine’s power is 50 kW. The car
moves down the same hill at the speed of 25 m/s while the engine working at
30 kW. Find the acceleration of the car when it moves downhill if given
resistance,R=v^2/k, where k is a constant and v is the velocity of car.