Q. A body of mass $5kg$ rests on a rough horizontal surface of coefficient of friction 0.2. The body is pulled through a distance of $10m$ by a horizontal force of $25\ N$. The kinetic energy acquired by it is $(g = 10\ ms^{2})$
A) $330\ J$
B) $150\ J$
C) $100\ J$
D) $50\ J$
Explanation
(b) Kinetic energy required by body
$= (Total\ work\ done\ on\ the\ body) - (work\ against\ friction)$
$= F \times S - \mu mgS = 25 \times 10 - 0.2 \times 5 \times 10 \times 10$
$= 250 - 100 = 150\ Joule$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.