Two bodies having equal masses are moving with uniform speeds of v and 2v respectively. Find the ratio of their kinetic energies.
Let the masses of the two bodies (m1) and (m2) be m kg
Let the velocity of the first body be v m/s
And the velocity of the second body be 2v m/s
Ratio of K.E = (KE) of body 1/ KE of body 2
= (1/2 mv2)/ (1/2 m (2v)2)
= v2/ (2v)2 = (1)2/ (2)2
= 1:4 (K.E∝v2)
Hence, the ratio of their kinetic energies is 1:4