Problem — Kinetic energy of a ball

Problem

A ball of mass $m = 0{,}40\;\mathrm{kg}$ is kicked at $v = 20\;\mathrm{m/s}$. Calculate its kinetic energy.

Solution

The kinetic energy of a body of mass $m$ moving with speed $v$ is $E_k = \frac{1}{2}\,m\,v^2$ Substituting the data: $E_k = \frac{1}{2}\cdot 0{,}40\;\mathrm{kg}\cdot (20\;\mathrm{m/s})^2 = \frac{1}{2}\cdot 0{,}40\cdot 400\;\mathrm{J}$ $\ev{E_k = 80\;\mathrm{J}}$

Links

Topics: Work and energy Concepts: Kinetic energy Skills: Symbolic setup Objects: Block