# An object travelling at 30m/(sec.) has kinetic energy 33,750 joules. What is its mass?

Dec 21, 2016

Mass of the object is $75$ kg.

#### Explanation:

Energy $E$ of an object of mass $m$ kg. travelling at $v$ $\frac{m}{\sec .}$ is $\frac{1}{2} m {v}^{2}$ joules.

Hence, mass is given by $\frac{2 E}{v} ^ 2$

As energy is $33 , 750$ joules and object is traveling at $30$ $\frac{m}{\sec .}$,

its mass is $\frac{33750 \times 2}{30 \times 30} = \frac{67500}{900} = 75$ kg.