Question

A force which varies with time $t$ as $\overrightarrow{F}=(3t\hat{i}+5\hat{j})$ acts on a body due to which its displacement varies as $\overrightarrow{s}=(2t^2\hat{i}-5\hat{j})$ where $t$ is in seconds. Work done by this force in initial $2s$ is:

• A. $23J$
• B. $32J$
• C. $0$
• D. $Ca{n}^{\prime }tbeobtained$

Answer 1

The correct option is A $23J$

$W=F.ds$

$W=(3t\hat{i}+5\hat{j}).(2t^2\hat{i}-5\hat{j})$

$W=6t^3-25$

$t=2sec$

$W=23J$