Question

In one-dimensional elastic collision of equal masses, the velocities are interchanged. Can velocities in a one-dimensional collision be interchanged if the masses are not equal?

Answer 1

That is not the concept of linear momentum conservation.

Explanation:

No, because it will not maintain the linear momentum.

Consider, for example, the one-dimensional collision of mass m with velocity 2v and mass 2 m before collision with velocity v.

Total momentum = m 2v + 2 mv = 4 mv.  

Had the speeds changed after the collision,

final momentum of the system would be = m v + 2 mv+2 mv = 5 mv,  

That is not the concept of linear momentum conservation. In this case, the velocities are not going to be interchanged.  

Answer 2

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