Comment by brickiex2 on 26/04/2023 at 16:42 UTC

45 upvotes, 2 direct replies (showing 2)

View submission: Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science

most people know that if you toss a basket ball in the air with "backspin", it will hit the ground and bounce towards you, if you use "forward spin" it will bounce away from you. However, it you spin the ball on your finger tip, like the Harlem Globetrotters, and drop the ball, it will hit the ground and reverse its spin, why is that?

Replies

Comment by propostor at 26/04/2023 at 17:31 UTC

62 upvotes, 1 direct replies

When it hits the ground, it compresses a little at the Impact point, causing the rotation contact to become a friction contact, which then "bounces" against itself and reverses the rotation.

Comment by fiddle-dee-dee at 26/04/2023 at 21:19 UTC

10 upvotes, 0 direct replies

The spin will also be reversed when bouncing in your first two examples.