Quote:Original post by shadow12345
Well, yes, that explanation helps. The conundrum I have is that the author defines angular impulse as:


M dt = I (Wa - Wb)

M = torque , I = moment of inertia, Wa = angular velocity after

That'd be right. Take the linear equivalent:

F = m A
F = m (dV/dt)
F dt = m (Va - Vb)

Okay, but what I was really getting at is that in one equation, they use

Jn,
but in anothe equation they use n!!!

Jn != n

As far as I know Jn is the normal component of the impulse force (which should be all components of the force, as it only acts along the normal of the collision), and n is the normalized normal of the collision.

That is why I'm confused. I've read over the paper posted, and the equations are essentially the same (also, it uses the conservation of momentum, but momentum isn't actually conserved because of inelasticity).