[pygame] sphere meets ground

[Douglas Bagnall <douglas@xxxxxxxxxxxxxxx>]

Patrick Mullen wrote:


> 
> But there IS an upward force, at least as far as my memory of the
> physics I learned.  The whole every action has a reaction business.
> If the ground were mobile, that gravity force down would cause the
> earth to move down with that same force.  Since the earth can't move,
> it pushes back with the force of gravity.

Yes, though in fact the upward force ends up being much greater than the
force of gravity, which is why the ball flies upwards.

With a given mass, force is essentially the same as acceleration. The
acceleration is known to be -1.8 * velocity in a single tick, but the
issue is how it is distributed within that tick.  The simplest way is
probably to (as Matt does) have the ball pause until the end of the tick
 before bouncing at full pace.


douglas