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 $10s$ is

• A. $50$ $J$
• B. $100$ $J$
• C. $125$ $J$
• D. $144$ $J$

Answer 1

Answer: (C)

$125$ $J$

Net force on body $=\sqrt{4^2+3^2}=5N$

$\therefore a=\frac{F}{m}=\frac{5}{10}=\frac{1}{2}m/s^2$

Kinetic energy $=\frac{1}{2}m{v}^2=\frac{1}{2}m{\left(at\right)}^2=125J$