How can I get the contact force?

[BBBBBbruce]

Hello, I am trying to obtain the collision force in a collision, but I am having some trouble getting the query.

Based on my search, physX is using PBD (I am not sure if XPBD is applied). I guess I can get the force directly from the impulse * delta_t = delta_p * mass.
May I ask if this impulse if the ContactPairPoint.impulse? if so which time is the delta_t? is it my time step for the gscene->simulate(time_step)?

Also, if XPBD is applied, maybe I can directly get the force from f = lambda* n / (ℎ^2)?

Thanks for the help.