Question

If the momentum ofa body is increased by 20% , then its kinetic energy increases by

• A. 44%
• B. 55%
• C. 60%
• D. 77%

Answer 1

The correct option is A 44%

As we know kinetic energy $K=\frac{1}{2}m{v}^2$

And momentum $P=mv$

$⟹K=\frac{P^2}{2m}$

When $P$ is increased by $20\%$

Then $K$ will be increased by$△K=\frac{(P\times 1.2{)}^2}{2m}=1.44K$

So, $\frac{△K}{K}\times 100=44\%$