- #1
Lotto
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- TL;DR Summary
- I throw a ball with a velocity ##v## against a bus moving towards me with a velocity ##-u##. What will be the ball's velocity after a perfectly elastic collision?
From the bus driver's point of view, who is at rest, the ball's initial velocity is ##u+v##. After the collision, its velocity has to have the same value, but an opposite direction, so ##-(u+v)##. So that means that relative to me standing on the ground at rest, the ball's new velocity is ##-(v+2u)##.
I understand this, but how to derive the new velocity from my point of view? I still can't explain why it is ##+2u## instead of ##+u##, I mean that the new velocity isn't##-(u+v)##. How to explain it? It is clear that it is because of the moving bus, but why in particular?
I understand this, but how to derive the new velocity from my point of view? I still can't explain why it is ##+2u## instead of ##+u##, I mean that the new velocity isn't##-(u+v)##. How to explain it? It is clear that it is because of the moving bus, but why in particular?