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I'm currently in the making of a small c++ simulation program and, as I am very new to physics, I am struggling with what seems to be a simple 2D collision handling problem. I spent quite some time thinking about it and looking at tutorials but I just don't really get it. Here is my problem :

One point (P) is colliding a (weightless) line attached to two other points (A and B).

P, A and B each have a specific velocity (Vp, Va, Vb) at the time of the collision and they have their own weight (Wp, Wa, Wb).

I know the exact coordinates of the collision (C) and all I want to know is how I need to modify the velocity for each of these 3 points. At the moment, I try to consider the impact point as a ball (I compute its velocity as Vc=Va*(1-||AC||/||AB||)+ Vb*(||AC||/||AB||) but I'm not sure if that is a correct approach and then I'm stuck at computing its mass).

Any help, hint or resource would be greatly appreciated. Here is a small diagram I made for explaining the problem.

Here is a small diagram I made for explaining the problem.

Petipo
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  • Try asking here: http://physics.stackexchange.com/ or here: http://gamedev.stackexchange.com/ – David Starkey Apr 19 '13 at 14:16
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    Well, that's a bit tricky, as I already did ask on physics.stackexchange, where they closed it, saying it was a topic for gamedev, moved my question to gamedev, where they said it was a question for physics.stackexchange. As I was in a "deadlock" situation, I finally decided to ask here so I could use my poor 11 reputation to add a picture... – Petipo Apr 19 '13 at 14:21
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    That's lame. This definitely belongs in the physics area. However, you may be able to find something helpful from this answer: http://stackoverflow.com/a/10056335/1618257 – David Starkey Apr 19 '13 at 14:31
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    @DavidStarkey: although the difference between a wall and a line is that in the case of the wall the whole force is used to bounce the ball whereas here the ball will bounce *and* the lines extremity will change their course (I guess). – Matthieu M. Apr 19 '13 at 15:27
  • Yes indeed, although the answer is interesting, it is this "line reaction" that gives me headaches. – Petipo Apr 19 '13 at 16:00
  • Might this be of some help? [conductor](http://www.chromeexperiments.com/detail/conductor/?f=) – gongzhitaao Apr 19 '13 at 16:20
  • Hmm... interesting problem. It may prove to be more complicated than it initially seems. I'll try and work on it. – Monkeyanator Apr 29 '13 at 13:52
  • Also, how would A and B have weights if they are simply endpoints of a line segment? Does the line segment have objects with certain weights at its endpoints? – Monkeyanator Apr 29 '13 at 13:57
  • @Monkeyanator yes the line segment is indeed connected to masses with certain weights. I didn't have time to try it so far but I think the answer implies the use of the conservation of momentum, energy and angular momentum equations. – Petipo Apr 29 '13 at 14:09
  • Definitely angular velocity would be involved. I'll work on this and try to get back to you :P – Monkeyanator Apr 29 '13 at 14:40
  • SO is not for "help, hint[s] or resource[s]" -- it is for concrete questions and answers about programming languages and pieces of code. – Lightness Races in Orbit May 27 '13 at 18:17

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