2019 Work, Energy and PowerCollisions – Elastic Collision in One Dimension Medium Question 19 of 71 in Work, Energy and Power

Body A of mass $4m$ moving with speed $u$ collides with another body B of mass $2m$, at rest. The collision is head on and elastic in nature. After the collision the fraction of energy lost by the colliding body A is:

A $\frac{1}{9}$
B $\frac{8}{9}$
C $\frac{4}{9}$
D $\frac{5}{9}$

The answer is B.

Solution

Fractional loss of KE of the colliding body in a head-on elastic collision: $\frac{\Delta KE}{KE}=\frac{4m_1m_2}{(m_1+m_2)^2}$ $=\frac{4\times4m\times2m}{(4m+2m)^2}=\frac{32m^2}{36m^2}=\frac{8}{9}$

Concept fraction of energy lost in an elastic collision

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71 questions from this chapter have appeared across 27 exam years.