Question

Sand is falling on a conveyor belt at rate of 5kg/s. the extra power required to move the belt with a velocity of 6 m/s is _____ ?

• A. $180W$
• B. $0.08W$
• C. $0.04W$
• D. $0.2W$

Answer 1

The correct option is A $180W$

F = rate of change of mass * velocity change

$\Rightarrow F=\left(5kg/s\right)\left(6m/s\right)$

$\Rightarrow F=30N$

Now,

Power = work done per second

P = force * rate of displacement

$\Rightarrow P=Fv=\left(30N\right)\left(6m/s\right)$

$\Rightarrow P=180W$