• # question_answer Sand is being dropped on a conveyor belt at the rate of M kg/s. The force necessary to keep the belt moving with a constant velocity of v m/s will be A)  Mv newton   B)  2 Mv newtonC)  $\frac{Mv}{2}$newton  D)  zero

Force required, $F=\frac{d(mv)}{dt}$ $=v\left( \frac{dm}{dt} \right)=v\,M$ as velocity v is constant, hence F = Mv newton