Question

Calculate the kinetic energy of a body of mass $0.1kg$ and momentum $40kgm{s}^{-1}$.

Answer 1

Calculate the kinetic energy

Given that,

mass, $m=0.1kg$

Momentum, $P=40kgm{s}^{-1}$

Velocity$=v$

We know that,

$P=mv$

Kinetic energy, $KE=\frac{1}{2}m{v}^2$

On replacing $v=\frac{P}{m}$,

$$\begin{gathered} KE=\frac{1}{2}m\times {\left(\frac{P}{m}\right)}^2 \\ KE=\frac{P^2}{2m} \\ KE=\frac{{\left(40\right)}^2}{2\times 0.1} \end{gathered}$$

$KE=8000J$

The kinetic energy of a body is $8000J$.