xmPuzzle 006 Bouncing on Slope


A ball is tossed and lands PERPENDICULARLY on a slope. Describe the subsequent trajectory of the ball. (Assume elastic collisions and negligible air resistance)


The ball will always bounce back to the same “height” above the slope, and the distance between bounces follow the arithmetic progression of 1, 3, 5, 7… units. (See below)


The easiest to see this is to resolve everything into two perpendicular components x and y: x parallel to the slope, and y perpendicular to the slope. It is then clear that the ball has a constant “downward” acceleration of gcosθ in the –y direction, and constant “rightward” acceleration of gsinθ in the +x direction.





Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s