Question

A body of mass m moving with velocity v collides head on with another body of mass 2m which is initially at rest. The ratio of K.E. of colliding body before and after collision will be [Roorkee 1982]
A) 1 : 1 B) 2 : 1 C) 4 : 1 D) 9 : 1

Answer 1

Explanation:

I think it is a elastic collision which forgot to mention.

although if so then simply use conservation of momentum as initial momentum = final one

then using formula of

e. coff. of restitution find velocities relation

here conservation of energy is also valid so using that u will easily find answer 9:4 not among options.