Question

A force of 5N acts on a 15 kg body initially at 4est. The work done by the force during the first second of motion of the body is:

• A. $5J$
• B. $\frac{5}{6}J$
• C. $6J$
• D. $75J$

Answer 1

The correct option is B $\frac{5}{6}J$

acc$=\frac{5}{15}=\frac{1}{3}m/s^2$

$v=u+at$

$=0+\frac{1}{3}\times 1$

$\frac{1}{3}m/s$

$\therefore K.E=\frac{1}{2}\times 15\times \frac{1}{9}$

$=\frac{15}{18}=\frac{5}{6}J$

$\therefore$ work done $=\frac{5}{6}J$

Hence,

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