Sand drops from a stationary hopper at the rate of 5 kg `s^(-1)` on to a conveyor belt moving with a constant speed of `2 m s ^(-1)` . What is the force required to keep the belt moving and what is the power delivered by the motor moving the belt ?
[ Hint: Tangetial force exerted on the belt = `u_("rel") (dM)/(dt)` where `u_("rel")` is the tangential relative velocity of the sand .]

Answer

10 N , 20 W