The energy possessed by a body because of its motion, equal to one half the mass of the body times the square of its speed is called its kinetic energy.
K=
2
1
mv
2
When, v=2v,
K
′
=
2
1
m(2v)
2
K
′
=4×
2
1
mv
2
K
′
=4K
Hence, when velocity is doubled, kinetic energy becomes 4 times.
