# Questions about collision and friction

I’m a beginner.
My questions are as follows:

1. If a small ball A collides with objects B and C respectively, how to achieve a collision recovery coefficient of 0.8 when A and B collide and 0.6 when A and C collide?
For example, when ball A collides with stationary B at a speed of 1m/s, the rebound velocity is 0.8m/s, and when ball A collides with stationary C at a speed of 1m/s, the rebound speed is 0.6m/s.
2. If an object A slides on objects B and C, how can the coefficient of friction be 0.8 when A slides on B and the coefficient of friction be 0.6 when A slides on C?
3. Which physics engine is better for the above functions? The built-in physics engine or the Bullet or ODE engine?

It would be great if a friend could give a code example.
Thank you!

idk how to do the sliding in the panda engine. There might be a collision handler that already does it. I built the stuff myself.

What you get is the fact that things have collided and that’s it. But since you have full information anyway, all the physics calculations can be done by you, any way you want.