A body of mass m, moving with momentum p and kinetic energy K are related as follows,
K=2mp2.
As the momentum of the body is increased by 20, then its momentum becomes,
(p+10020p)=1.2p
and the mass of the body remains unchanged. So, kinetic energy is directly related to the square of momentum.
Hence, new kinetic energy (K′) will be,
K′=2m(1.2p)2
K′=1.44K.
So, the percentage change in kinetic energy
=KK′−K×100
=K1.44K−K×100
=(1.44−1)×100
=44.