# Help needed force on objects

1. Sep 10, 2009

### Gohtar

I have been racking my brains for 2 days.

I am working on a homebrew video game and am having problems with the physics.

say i have 3 objects, one moving left to right(1) the other 2 moving right to left(2,3).

they all have the same mass and velocity.

Say the mass is 100 units and the velocity is 1 unit.

So far i have been able to get the code to work where if object1 collides with object2 then they both stop moving. What I want to happen is if object3 collides with the back of object2 that it will transfer it's force to both objects and I will get movement in all 3 in the right to left direction.

Friction is zero, not a factor in this.

I think what I am mostly stuck on now is how to calculate the velocity of the group of objects when that 3rd one starts pushing.

Thanks

EDIT

forgot to mention, right now i am only dealing in a 2d plane with the forces only being applied in the X axis.

Last edited: Sep 10, 2009
2. Sep 10, 2009

### Staff: Mentor

Welcome to the PF. Sounds like you are modelling elastic collisions. Think "conservation of linear momentum"

http://en.wikipedia.org/wiki/Momentum#Elastic_collisions

Why would two objects stop moving if they collide? Wouldn't they bounce back apart?

3. Sep 10, 2009

### Gohtar

No i am thinking more bulldozer type collisions, it hits the other object and starts moving it if it can, no bounce. I am not going for realism at all here.