Two identical gliders slide toward each other on an airtrack. One moves at 1 m/s and the other at 2 m/s. They collide and stick. The combined mass moves at ____ m/s.

Question

Two identical gliders slide toward each other on an airtrack. One moves at 1 m/s and the other at 2 m/s.  They collide and stick.  The combined mass moves at ____ m/s.
Answer