JEE Main Physics question
A body of mass m₁ collides elastically with another body of mass m₂ at rest. If the velocity of m₁ after collision becomes 2/3 times its initial velocity, the ratio of their masses is
Answer: (B)
Solution
v₁' = [(m₁−m₂)/(m₁+m₂)]u₁ = (2/3)u₁ ⟹ 3(m₁−m₂) = 2(m₁+m₂) ⟹ m₁ = 5m₂ ⟹ m₁:m₂ = 5:1.