Question

What is the kinetic energy of a 150 kg rock thrown 75 m/s?

Answer 1

The relation between the mass, velocity and kinetic energy is,

`K=(1)/(2)mv^2`

where m is the mass of the rock, v is the velocity.

Substituting the known values,

`\begin{gathered} K=(1)/(2)*150*75^2 \\ K=421875 \\ K=421.9\text{ kJ} \end{gathered}`

Thus, the kinetic energy of the rock is 421.9 kJ.