as a van travels along a level stretch of road with constant speed, most of the power developed by the engine is used to compensate for the energy transformations due to friction forces exerted on the van by the air and the road. if the power developed by the engine is 1.50 hp, calculate the total friction force acting on the van (in n) when it is moving at a speed of 27 m/s. one horsepower equals 746 w.