Question

An engine pumps water through a hose pipe. Water passes through the pipe and leaves it with a velocity 2 m/ s The mass per unit length of water in the pipe is 100 kq/m. What is the power of the engine?

• A. 400 W
• B. 200 W
• C. 100 W
• D. 800 W

Answer 1

The correct option is D 800 W

Power if the force is constant$-$

$P=\frac{dw}{dt}=P=\overrightarrow{F}\cdot \overrightarrow{v}$

where in$,$

$\overrightarrow F \to force\$

$\overrightarrow{v}=velocity$

Mass per unit of water$,$ $\mu =100kg/m$

Velocity of water $V=2m/s$

Power of the engine $P=\mu v^3=\left(100\right)\times {\left(2\right)}^3$

$P=800W$

Hence,

option $\left(D\right)$ is correct answer.