Question

A motor drives a body along a straight line with a steady force $F$. If the body moves with velocity $V$ the power $P$ developed is:

• A. $F{V}^2$
• B. $FV$
• C. $\frac{F}{V}$
• D. $\frac{F}{V^2}$

Answer 1

The correct option is B $FV$

$P=FV$

we know that

power $=\frac{dw}{dt}$

Now, $w=F.ds$

$dw=F.ds$

$\frac{dw}{dt}=F.\frac{ds}{dt}$

$P=F.v\because \frac{ds}{dt}=v$