A bullet is fired from a rifle. The rifle is free to recoil. Compare the kinetic energy of the rifle with that of the bullet .

Explanation

`K.E , K =1/2 mv^2 =1/2 ((mv)^2)/(m) =(p^2)/(2m)` [ p=momentum ]
Both the rifle and the bullet were at rest before firing . After firing , the momenta of the rifle and the bullet must be equal in magnitude and opposite in direcition in order to conserve linear momentum.
As p is the same for both `K prop 1/m`. As the rifle is heavier, its K.E is less than that of the bullet.