A bus of mass 6 metric tons is pulled at a speed of 18 KMPH an up incline of inclination 1 in 20. Power of the engine is, (g = $10m{s}^{-2}$)

P =FV

The static frictional force F applied by the road on the wheels = mg sin θ

This force F is responsible for the motion of the bus

.: Power = FV = mg vsin θ

 = 6000 x 10 x (18 x 5/18) x 1 / 20 W

= 15 KW