1 Joule = ?

A man of mass 20 kg is running in a straight line with velocity 10 m/s. What is value of his kinetic energy?

If a ball rebounds two thirds as for as it falls , how far will it travel before coming to rest if it is dropped from a height of 30 meters ? ( Total distance it travels is the sum of a series) 

The velocity $(v)$ of a particle of mass $m$ moving along x-axis is given by $v = \alpha \sqrt {x}$, where $\alpha$ is a constant. Find work done by force acting on particle during its motion from $x = 0$ to $x = 2m$.

When the speed of a body is doubled, its kinetic energy becomes ;