Two gliders having the same mass and speed move toward each other on an air track and stick together (an air track produces a more frictionless surface for objects to travel on). After the collision, the velocity of the gliders is
A. twice the original velocity
B. one half the original velocity
C. zero
D. the same as the original velocity
E. There is not enough information to say.
Since these in essence cancel each other's velocity in the original directions they were headed and eventually stick together, the only logical answer is that their velocity would be zero.