Question

Sand falls vertically at the rate of $2kg/s$ on a conveyor belt moving horizontally with a velocity of $0.2ms$.
The extra force required to keep the belt moving is

• A. 0.4 W
• B. 0.08 W
• C. 0.04 W
• D. 0.2 W

Answer 1

The correct option is C 0.04 W

$v=0.2m/s$

$\Rightarrow$ Force $=\frac{d}{dt}\left(mv\right)$ $\frac{dm}{dt}=2kg/s$

$=v\frac{dm}{dt}$ $v=$ constant

$=0.2\times 2$

$=0.4N.$

Hence, the answer is $0.4N.$