Question

Power versus time graph for a force is given below. Work done by the force upto time $t(\le t_0)$,

• A. First decreases then increases
• B. First increases then decreases
• C. Always increases
• D. Always decreases

Answer 1

The correct option is C Always increases

We know that, power of a force is given by, $P=\frac{dW}{dt}$
where $dW$ is work done in time interval $dt$.
$\Rightarrow dW=Pdt=$ Area under $P-t$ graph.

The work done by force from time $t=0$ to $t=t_o\text{sec}$ is given by shaded area in graph below.
We can see that, as $t$ increases, this area increases.


$\therefore$ Work done by force keeps on increasing.