Question

a block of mass 20 kg is moving with constant velocity along an inclined plane of inclination 37 degree with the help of a force of constant power 50 that if the coefficient of kinetic friction between block and the surface is 0.25 then what fraction of power is used against Gravity

Answer 1

From equilibrium of forces along the incline,

mgsinθ + mgcosθ = F

⇒ F= 160N

Power=Fv=constant=50W

⇒ v= 5/16 m/s

Power used against gravity= Fv =mgsinθ v = 37.5W

Hence fraction of power used= 37.5/50 = 3/4

Answer 2

You can solve it in many ways ......just focus of definition ..................