Question

A car of mass 2500 kg is driving up a hill inclined at an angle of 10° to the horizontal. If the

resistance to motion is 3.5 kN, and the speed is a constant 20 m/s, find the power exerted.

Answer 1

$$v=const$$

$$a=0$$

$$F-F_r-mgsin10^0=0$$

$$F=F_r+mg sin10^0$$

$$F=3,500+2,500\times9.8\times 0.17=7,752 N$$

$$P=Fv$$

$$P=7,752\times20=155,040 W=155 kW$$