array9

When a hit fives ball bounces for the first time, it is obvious that the ball slows down and rises at a slightly higher angle because of that.  If you look at the vertical movement only, there is no difference from it just bouncing.

But in the horizontal plane, the ball transfers some energy to the ball in the firm of spin, and so clearly slows down from that horizontal impulse.

Maybe a third of the horizontal energy is transferred, and so the ball slows to the square root of two thirds the original horizontal speed.  So something like a twenty percent drop.  Depends on how slippery the surface is.

So the angle if incidence does not equal the angle of reflection.  And this is easily seen by the player.

But translate this into bounces on the wall, horizontal or vertical, and players just dont see it.  But the same inequality is there.  It is less because gravity is not involved in the bounce.

It might add to the visual effect of the ball shooting low into the court when it hits side wall and the floor, as the ball does not hit the floor quite as vertically as one thinks. And the spin it has got reduces the exit angle even more.

My main point is peoples difficulty in changing their perspectives.

It can be useful to see the double bounce, wall and floor, as a device that diverts energy to and from one direction to another, working in either direction.

Hit the floor first and it will go higher and slower.  Hit the wall first and it will come out faster and lower.  Angles of incidence and reflection are all over the place.

Never happens with light?  Or racquet balls.  What about particles?  Can one apply any torque to them, or are all forces acting at the cetre of gravity?

No wonder fives players cannot play racquets.

M