Okay, suppose 2 identical bodies/particles(i.e., of equal masses) moving with same velocities approach each other and have an elastic collision.
Now, as there is elastic collision in between them, both of them will rebound and move in opposite direction with same velocity.(Source: Directs to Quora(Refer to Mohd. Faiz Answer))
Here's the doubt: I don't think so there could be any elastic collision when 2 identical bodies with same speed moves towards each other.
Why there is such doubt in my mind? :-
I know I stated Elastic Collision and thus, so to conserve Kinetic Energy, they should rebound with same velocity.
Now, please read this clearly.
Consider the same identical bodies/particles, A and B approaching each other with same velocity and have an elastic collision. As there is elastic collision, during time of collision, there will be conservative forces acting on the bodies.
Now equal and opposite conservative forces $F_{AB}$ and $F_{BA}$ acts on bodies A and B respectively. The conservative forces will make the bodies to rebound and thus, the bodies will go away from each other, i.e, the bodies will move in direction of conservative forces.
Hence, both the conservative forces $F_{AB}$ and $F_{BA}$ will do Positive Work on particles A and B respectively.
As per Work-Energy Theorem, Work(Force)=Change in Kinetic Energy of the Body
So, Positive Work By Conservative Forces = Increase in Kinetic Energies of bodies
In other words, $u_A < v_A$ and $u_B < v_B$ such that Initial Total KE < Final Total KE
But this couldn't be possible if the collision is Elastic as, in Elastic Collision Total Kinetic Energy remains conserved.
So, where am i going wrong?
Please correct me.
Note: I know in reality there cannot be any Elastic Collision at macroscopic level. But here i have assumed that the bodies are perfectly rigid and no ext. force is acting on them. Also the mechanical energy do not converts into any forms