Question

Two bodies of equal masses are moving with uniform velocities v and 2v. Find the ratio of their kinetic energies.

Answer 1

K.E = `1/2 mv^2`

K.E = `1/2 m (2v)^2`

K.E = `(1/2 mv^2) xx 4`

∴ Ratio of their K.E = `(1/2 mv^2)/(4(1/2 mv^2))`

= `1/4`

= 1 : 4

Ratio of K.E. of A and B is 1 : 4.