Question

A body of mass $m$ is moving in a straight line at a constant speed $v$. Its kinetic energy is $K$ and the magnitude of its momentum is $p$. Which of the following relations are correct?

• A. $p=\sqrt{2mk}$
• B. $p=\sqrt{\frac{2k}{m}}$
• C. $2K=pv$
• D. $v=\sqrt{\frac{2k}{p}}$

Answer 1

The correct option is A $p=\sqrt{2mk}$

formulae,

Kinetic energy K

$K=\frac{1}{2}m{v}^2$

momentum P

$P=mv$

$K=\frac{1}{2}v\left(mv\right)$

$K=\frac{1}{2}\frac{P^2}{m}$

$\therefore P=\sqrt{2mK}$