Question

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 $25N$. The K.E. acquired by it is

• A. $200J$
• B. $150J$
• C. $100J$
• D. $50J$

Answer 1

The correct option is B $150J$

Kinetic energy acquired by the body is,
$K.E.=F_{net}\times s$
Also,
$F_{net}=F_{applied}-f$
$f=\mu mg$
$f=0.2\times 5\times 10=10$
$\therefore F_{net}=25-10=15$
$\therefore K.E.=15\times 10=150J$