A body of mass 2 kg makes an elastic collision with another body at rest and continues to move in the original direction but with one - fourth its original speed . What is the mass of the body it collides with ?

Options

A. 1.0 kg
B. 1.5 kg
C. 1.8 kg
D. 1.2 kg

Answer

D

Explanation

COM gives: `2v_0 = 2 xx (v_0)/4 + mv" "` ...(i)
For elastic collision `v - (v_0)/4 = v_0" "…..(ii)`
From (i) and (ii) `m = 12 kg`.