Question

A 54 kg cannon ball has 27378 J of KE. How fast is it going? Round to nearest whole.

Answer 1

Kinetic energy of a body of mass m is given by,

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

where v is the speed of the body,

Given,

`\begin{gathered} m=54\text{ }kg \\ K.E.=27378\text{ }J \end{gathered}`

Therefore,

`\begin{gathered} 27378=(1)/(2)(54)v^2 \\ \Rightarrow v=\sqrt{(2*27378)/(54)}\text{ }(m)/(s) \\ \Rightarrow v=31.84\text{ m/s or 32 m/s} \end{gathered}`

Result: The cannon ball is going at a speed of 32 m/s.