Question

A body of mass $10kg$ at rest is acted upon simultaneously by two forces $4N$ and $3N$ at right angles to each other. The kinetic energy of the body at the end of $10sec$ is ......

• A. $100J$
• B. $300J$
• C. $50J$
• D. $125J$

Answer 1

The correct option is D $125J$

$F_{net}=\sqrt{3^2+4^2}=5$N

F=ma

$5=10a$

a=$\frac{1}{2}m/s^2$

v=u+at=$\frac{1}{2}10=5m/s^2$

KE=$\frac{1}{2}m{v}^2=\frac{1}{2}10\times 5^2=125J$