Question

Two bodies of equal masses move with uniform velocities v and 3v respectively.Find the ratio of their kinetic energies.

Answer 1

We know that kinetic energy is given as

E = (1/2)mv²

now,

for body 1

E₁ = (1/2)mv²

and

for body 2

E2= (1/2)m(3v)²

= (9/2)mv²

so,the ratio will be

E₁/E₂ = [(1/2)mv²] / [(9/2)mv²]

thus,

E₁/E₂ = 1/9