Question

Sand is being dropped on a conveyorbelt at the rate of $Mkg{s}^{-1}$. The force necessary to keep the belt moving with a constant velocity of $vms-1$ will be

• A. $Mvnewton$
• B. $2Mvnewton$
• C. $\frac{Mv}{2}newton$
• D. $Zero$

Answer 1

The correct option is A $Mvnewton$

Per second the mass of conveyor belt will increase by M Kg .

Let its initial momentum be A.

So By conservation of momentum,

A+Ft=A+rate of sand being dropped$\times$vt

So F=Mv newton