In rigid body simulations, external forces create two different kinds of effects on an object: linear acceleration and angular acceleration. Linear acceleration is how fast an object is moving incrementally, and angular acceleration is how fast an object is spinning incrementally.
To obtain the net external force on a single vertex or edge doesn't really make sense, because a vertex or edge doesn't have any volume and therefore doesn't have any mass. In the equation F=ma (Newton's second law of motion), solving for a, a=F/m, since a vertex or edge doesn't have any mass, the acceleration due to the force would be undefined, because you're dividing by 0. Forces have to be applied to masses. Therefore, when a rigid body is affected by a force, the force is applied throughout the entire mass, producing a linear and maybe angular acceleration.
To get the velocity vector, you need to use cross multiply the angular velocity with the vectorial distance of the vertex from the center of mass, and then add that to the linear velocity. (More info)
In script, it should look something like this:
v = object.getLinearVelocity(False)
omega = object.getAngularVelocity(False)
r = Vector((1,1,-1)) # offset of vertex (or point) from center of mass.
v_net = v + omega.cross(r)
Make sure you import the
Vector class from