Question

Gravels are dropped on a conveyor belt at the rate of $0.5kg/sec$. The extra force required in $newton$ to keep the belt moving at $2m/sec$. is:

• A. $1N$
• B. $2N$
• C. $4N$
• D. $0.5N$

Answer 1

Answer: (A)

$1N$

The net force given on the system is given as:

$F=u\frac{d(mv)}{dt}$

$=u\frac{dm}{dt}$ + $m\frac{dv}{dt}$

Here, v is constant as mentioned in the question itself

Hence, $\frac{dv}{dt}=0$

Thus, $F=u\frac{dm}{dt}=2\times 0.5=1N$