Two objects having equal masses are moving with uniform velocities of 2 m/s and 6 m/s respectively. Calculate the ratio of their kinetic energies.
Let the velocity of the first body, v1 = 2m/s (given)
And the mass of the first body, m1= ‘m’ kg
Similarly, let the velocity of the second body, v2 = 6m/s (given)
And the mass of the second body, m2 = ‘m’ kg
Kinetic energy, K.E. = 1/2mv2
Therefore, K.E of the first body = 1/2 x m x (2)2
K.E of the second body = 1/2 x m x (6)2
Ratio of their kinetic energies = 1/2 x m x (2)2/ 1/2 x m x (6)2
= 4/36
= 1/9
Hence, the Ratio of the kinetic energy of body 1: Ratio of the kinetic energy of body 2 = 1:9