If you pull one ball away from the end and release it, it will collide with the row of other balls, and one ball at the opposite end of the row will fly upward to almost the same height from which the...If you pull one ball away from the end and release it, it will collide with the row of other balls, and one ball at the opposite end of the row will fly upward to almost the same height from which the original ball was released. Before the collision, the momentum of the system (due to the motion of the first ball) is p=mv; after the collision, the momentum of the system in this case would be p=m(v/2)+m(v/2)=mv, and momentum is still conserved.
