How to get the support force of rest object?

[qingteng]

Hi, I want to extract the value of force from bullet. Now I can get the force during collision:
float impulse = pt.getAppliedImpulse();
Result[is].ContactPoint[ip].Force = impulse*60;

My question is how I can get the support force (or impulse) of a static object on ground. Since the object is rest on the ground, I think there is no penetration or impulse.

Many thanks