Question

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

• A. 32 J
• B. 24 J
• C. 46 J
• D. 20 J

Answer 1

Answer: (A)

32 J

$W=\int \overline{F}.\overline{ds}$

$\overline{d}s=4t\hat{i}dt$

$dW=(3t\hat{i}+5\hat{j}).\left(4t\hat{i}\right)dt$

$W(t=2)=\int 12t^{2}dt=4t^3=4\left(2^3\right)=32J$