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JEE Main 202118 MarchEvening Shift
Exam
JEE Main
Year
2021
Date
18 March
Shift
Evening Shift
Subject
Physics
Chapter
Center of Mass, Momentum and Collision

JEE Main 2021 · 18 March · Evening Shift · Physics · Center of Mass, Momentum and Collision

An object of mass m _ 1 collides with another object of mass m _ 2...

An object of mass m1{m}_{1} collides with another object of mass m2{m}_{2}, which is at rest. After the collision the objects move with equal speeds in opposite direction. The ratio of the masses m2:m1{m}_{2}: {m}_{1} is :An object of mass m _ 1 collides with another object of mass m _ 2 , which is at rest. After the collision the objects

Options

  1. A3:13: 1
  2. B2:12: 1
  3. C1:21: 2
  4. D1:11: 1

Correct answer

A. 3:13: 1

Step-by-step solution

An object of mass m _ 1 collides with another object of mass m _ 2 , which is at rest. After the collision the objects

m1v1=−m1v+m2v{m}_{1}{v}_{1} = - {m}_{1}v + {m}_{2}v

v1=−v+m2m1v{v}_{1} = - v + \dfrac{{m}_{2}}{{m}_{1}}v

(v1+v)v=m2m1\dfrac{\left({v}_{1} + v\right)}{v} = \dfrac{{m}_{2}}{{m}_{1}}

e=2vv1=1e = \dfrac{2v}{{v}_{1}} = 1

v=v12v = \dfrac{{v}_{1}}{2}

v1+v1/2v1/2=m2m1\dfrac{{v}_{1} + {v}_{1} / 2}{{v}_{1} / 2} = \dfrac{{m}_{2}}{{m}_{1}}

3=m2m13 = \dfrac{{m}_{2}}{{m}_{1}}

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