Given a circular billiards table with center O,
radius r, and no pockets. A cue ball (with a
radius negligible compared to r) is placed at
point A such that 0<OA≤r. The ball is struck
and bounces off the cushion twice before
returning to point A.
How was the direction of the shot determined?
(In reply to
re(2): Obvious?? by brianjn)
I think what's wanted is a relation such as:
When OA/r = .9, the angle of the shot with the ray to the center is 32.4°.
When OA/r = .75, the angle of the shot with the ray to the center is 36.8°.
When OA/r = .5, the angle of the shot with the ray to the center is 47.1°.
with some sort of functional ralationshipe between OA/r and the required angle.
The numbers are approximations derived from moving the first point of reflection along the circle while seeing the ray after the second reflection off the circle go through various locations of the initial point.

Posted by Charlie
on 20130423 23:21:21 