Pool players figure out how to hit a ball without shooting d

Pool players figure out how to hit a ball without shooting directly at it ? Explain the principle they employ.

Solution

When two bodies collide each other momentum is redistributed (conserved). If a ball of mass m and velocity v collides with a statinary ball of same mass and at rest their velocities are exchanged. So a pool player need not hit the ball directly. He rathers makes one ball collide with the other. In any collision momentum is conserved.