Make my ball ONLY bounche up

I made a small ball game with the new 2d functions. Ive made some platforms, and the player which is the ball. i added physic material to my ball, so it constantly bounches. But when it hits the edge of my platform colliders it bounches to the side. (Imagine if you bounched a ball in real life into the edge of a table) How do i make it stop during that?

Constrain the rigidbody to move only in the y direction so that bouncing in x direction is not considered.