Four nearly identical ball bearings sit at rest together at the bottom of a symmetric ramp. A fifth ball is dropped from one end of the ramp which clashes with the stationary balls at the bottom causing opposite sphere to be launched off the other end of the ramp. Where did the extra energy come from?

The sphere the dropped ball hits is magnetic therefore increasing the KE of the dropped ball which is transfered to the end ball bearing, launching it off the track. 

 

Magnetic Potential Energy