# Triangle-wall collision

## Main Question or Discussion Point

Hi, how can I calculate the reaction a triangle with a certain speed and angle has upon hitting a wall?

I wish to be able to know the angular and linear velocity it has after the collision.

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Lok
More information needed. Like Triangle (what is it made of, elastic inelastic etc) angle of impact (plane vs. wall), type of collision, any friction involved?, this kind of stuff.

I guess I should've said that this is in a 2D environment. It's just a rigid equilateral triangle, no friction, any angle.

Maybe this picture can help.

http://img715.imageshack.us/img715/1409/collision.png [Broken]

The speed the triangle has before the collision is 1m/seg and its mass is 2kg.

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Lok
In this case you can simplify everything, drop the mass as it is useless, the triangle can be seen as a point mass object with 3 weightless bars around it. You can start by separating the forces on Ox and Oy (triangle reference frame is best Oy being between center and corner) then Ox will drive the angular component and Oy will be the ellastic collision.

A further complication as in the above picture is if the angular from the first collision drives the tringle with another corner into the wall. That is where the fun stops. :P

I started to type a "the fun would stop when" bla bla, then I realized... I was saying the same thing as Lok, but with a lesser understanding of the underlying theory!!

Lok
I guess I should've said that this is in a 2D environment. It's just a rigid equilateral triangle, no friction, any angle.
Btw. are you sure you want no friction or just no air friction, as that would mean the corner hits the wall, slips along it and the side slams finally into the wall transforming any angluar momentum gained into an elastic collision, aka just a simple almost vertical bounce.

As you have seen speed and mass, play little importance to the geometric outcome of the collision. Any classical value will have the same angle and angular momentum (proportional to the speed). But for simplicity's sake get some unitary values.