Q122 / 270 · NDA 2023 (Phase 1) · General Ability
Sand falls vertically on a conveyor belt at a rate of 0.1 $\mathrm{kg} / \mathrm{s}$. In order to keep the belt moving at a uniform speed of $2 \mathrm{~m} / \mathrm{s}$, the force required to be applied on the belt is :
- A0 N
- Correct answerB0.2 N
- C1.0 N
- D2.0 N
Solution
According to question
Speed, $v=2 \mathrm{~m} / \mathrm{s}$
$\frac{\mathrm{dm}}{\mathrm{dt}}=0.1 \mathrm{~kg} / \mathrm{s}$
Force $=\frac{\mathrm{d}}{\mathrm{dt}_1}(\mathrm{mv})$
$=v \frac{d \mathrm{~m}}{\mathrm{dt}}$
$=2 \times \mathbb{W} .1=0.2 \mathrm{~N}$
Hence, the correct answer is option: 'B'.