The kinetic energy of an object of mass ‘$m$’ moving with a velocity of $5\ ms^{-1}$ is $25\ J$. What will be its kinetic energy when its velocity is doubled ?

As given, mass of the object $=m$

Velocity of the object $v=5\ ms^{-1}$

Kinetic energy of the moving object $K=25\ J$

Or $\frac{1}{2}mv^2=25$

Or $m( 5)^2=50$

Or $25m=50$

Or $m=\frac{50}{25}=2\ kg$

When the velocity is doubled, the velocity becomes $v=2\times5=10\ ms^{-1}$

Kinetic energy when the velocity is doubled $=\frac{1}{2}\times2\times( 10)^2$

$=100\  J$