Question

A girl who weighs 30 kg is inline skating at a speed of 5 m/s. What is the girl’s kinetic energy?

Answer 1

Answer & Explanation:

The kinetic energy is given by

$K = \dfrac{1}{2} m v^2 \, \, ,$

where $m$ is the girl's mass and $v$ is its speed. We can plug in the values to obtain the result,

$K = \dfrac{1}{2} ( 30 \, \text{kg} ) ( 5 \, \text{m} / \text{s} )^2 = 375 \, \text{J} \, \, .$

Note the unit used to write the result, it is the Joule ( $\text{J}$ ).