Sand drops from a stationary hopper at the rat of `5 kgs^(-1)` onto a conveyor belt moving with a constant speed of `2 ms^(-1)`. What is the force required to keep the belt moving and what is the power delivered by the motor moving the belt ?

Explanation

Impulse J = Ft = mv, `F=(mv)/(t)`
`v=2 ms^(-1), (m)/(t)=5 kgs^(-1) rArr F=10 N`
Powe `P=(W)/(t)=(Fs)/(t)=Fv = 10xx2=20` watt.