televi T asked:

An elliptipool is an elliptical pool table with only one pocket. A pool shark places a ball on the table, hits it in what appears to be a random direction, and yet it bounces off the edge, falling directly into the pocket. Explain why this happens

Question posted courtesy of: Judy

One Response to “An elliptipool is an elliptical pool table with only one pocket. A pool shark places a ball on the table, hit”

1. notthejake on March 20th, 2008 5:28 am

   Ah, the good old elliptical pool table:

   the ball is put at one focus; the pocket is at the other.

   Any ray passing through one focus will reflect directly into the other one; therefore, he could hit the ball anywhere and it will bounce and fall directly into the pocket.

   Or, as long as the pocket is at one focus, the ball can be put anywhere else and hit either directly at or directly away from the other focus (in either direction on the line connecting the other focus and the ball). It will then bounce once and fall into the pocket.

   Or… it could be hit directly away from the pocket, it will then bounce, pass over the other focus, bounce again and fall into the pocket.

   As long as the pocket is at one focus, this will happen.