The throw floor → underside of the table → floor
the ball and its path
contact-point velocity u
where it started
where it ends up
What actually sets the rebound the headline, tested
incoming, fixed at 25°
outgoing, one ray per spin
what “angle in = angle out” predicts
Inside one contact where et actually comes from
normal force
tangential force
contact-point velocity u
The bounce, as a matrix
Acting on (vx, Rω), the two numbers the contact point cares about. Its trace is 1 − et and its determinant is −et, for every α.