Momentum:difference in final velocities

  • Thread starter Sprinkle159
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  • #1
If the initial velocities of 2 particles are given, and the masses are equal, then is there some limit on what the final velocities can be?


(initial velocity of particle 2 is zero; v2i=0)


To clarify my question if particle 1 has an initial velocity of 50 m/s, then this equation says the final velocity of particle 1 could be -550 m/s, and then the final velocity of particle 2 would be 600 m/s, which are much larger then the initial velocity of particle 1. So is there some limit on what values the final velocities can have?
  • #2
Yes. The collision would also need to satisfy conservation of energy.
  • #3
... and that means that (in your example, where the masses are equal and particle 2 is initially at rest with the reference frame), there are two extreme possibilities [particle 1 stops and particle 2 takes particle's 1 initial velocity (perfectly elastic collision) and both particles stick to each other and move with velocity = 0.25 m/s (perfectly inelastic collision)] and a range between them but not beyond.

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