Question

A 1600-kg car experiences a combined force of air resistance and friction that has the same magnitude whether the car goes up or down a hill at 32 m/s. Going up a hill, the car's engine produces 54 hp more power to sustain the constant velocity than it does going down the same hill. At what angle is the hill inclined above the horizontal?

Answer 1

54 hp = 40,284 Watts

Difference between uphill and downhill power = 2*(weight)*(speed)*sinA

sinA = 40,284/[2*1600*9.8*32] = 0.04014
A = 2.3 degrees