https://docs.nvidia.com/gameworks/content/gameworkslibrary/physx/apireference/files/classPxRigidBody.html#efe5174aa160a07d488de2a18ba61f94

currently, "addForce" is not suitable for constant per frame input as there is no good way to measure the effect.

there are other commands in the nvidia library, namely "clearForce and "clearTorque

these would be useful for per-frame force control