Question about soft body

I am learning the samples/bullet-physics/, and I have two questions:

  1. When running the, the soft cube is swing all the time and cannot be static. Even I add the damping/friction, the soft cube still can not be static.

    In my thought, the soft cube fall on the ground, and it should be static after some time.

  2. I can add force to a soft cube by softNp.node().add_force(force). Where does the force is applied? Is it possible to assign position where the force is applied? For example, for a cuboid 2x2x10, how to applied force in 1x1x10?

Any suggestion is appreciated~~~