Question

Two bodies of equal mass move with uniform velocities u and 4 u respectively. Find the ratio of their kinetic energies.

Answer 1

K.E1 : K.E2 = 1 : 16

Answer 2

Let mass of 2 bodies be m

Hence velocity of 1st body is u and

Velocity of 2nd body is 4u

Kinetic energy of 1st body = 1/2mu²

Kinetic energy of 2nd body = 1/2m(4u)²

Thus we will get ratio as 1/16.