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NEET-XII-Physics
P1 year:2019
- #4Body 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 :
(1)``\frac19``
(2)``\frac89``
(3)``\frac49``
(4)``\frac59``digAnsr: 2Ans : ( 2 )
Sol. Fractional loss of KE of colliding body
``\frac{\Delta KE}{KE} = \frac{4m_1m_2}{(m_1 + m_2)^2}``
On substitution ``m_1= 4m, m_2 = 2m``
= ``\frac{4.4m.2m }{ (4m+2m)^2} = \frac{32}{36}= \frac89``