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QNEET-2019-Ph-798: NEET 2019 Physics - Class 11 NEET-2019-Ph-798 Solution: Body A of mass 4m moving with speed u collides with another…
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: 5/9 4/9 8/9 1/9
Multiple Choice Options
- A 9 5 _
- B 9 4 _
- C 9 8 _
- D 9 1 _
Step-by-Step Verified Solution
As linear momentum is conserved before and after the collision,
_ 4m _ u = 4m _ v 1 + 2m _ v 2
_ 2u = 2v 1 + v 2 ......(1)
As collision is elastic so e = 1
We know, e = v 2 _ v 1 u 1 _ u 2
_ 1 = v 2 _ v 1 u _ 0
_ u = v 2 - v 1 ....(2)
Subtractiong (2) from (1), we get
u = 3v 1
_ v 1 = u 3
After the collision the fraction of energy lost by the colliding body A is
= 1 2 ( 4 m ) u 2 _ 1 2 ( 4 m ) ( u 3 ) 2 1 2 ( 4 m ) u 2
= 1 _ 1 9 1 = 8 9