In thinking about how to communicate an idea I have, I started to experiment with tennis ball - throwing it in different ways to achieve different aspects of flight - straight ball, sinker, curve, etc.
Then I had a session with one of the young golfers I coach, and watching him hit wedges reminded me of all the times I've heard the term, "geared effect".
This relates specifically to the angle of the club face at the point of impact, and the direction of the shear forces acting through the face of the club against the surface of the ball.
Could it, I murmured to myself, be something to consider with particulate motion and laminar flow?
What could be "imparting" the energy required to create the "spin" motion and thus part of the momentum (vector) to the particle? How would you describe the surface / impact point?
I'm still thinking about it all, particularly as it might apply in a vacuum.
Anyone care to help me out here?