I've made a program which is supposed to simulate free fall of a ball on a ground.
For collision with the ground I relied on calculating the impulse force with the answer in this Phys.SE question but I think the law is, well, wrong, the force must be a very big force acting on short time.
The program didn't work, the ball went through the ground, I'm sure I applied the impulse force and the Normal force together, the force is greater than weight but is still small.
I have a working collision detection and I know the velocity of the ball before collision, what I want to know is the instantaneous impulse force acting on the ball on collision with the ground.
So , how to do that ? and why is this force so enormous that it stops the ball almost instantly ?
In this program I define $dt$ as constant equals to 0.1, then I simply say :
$$dv=(F/m)*dt$$ $$dl=dv*dt$$ I do these calculations for each frame .
this way I don't have to use integrals and I ease the calculations, though they won't be accurate but it's hard for a computer to simulate the world literally .