In: Physics
A billiard ball is shot east at 2.80 m/s. A second, identical billiard ball is shot west at 1.20 m/s. The balls has a glancing collision, not a head-on-collision, deflecting the second ball by 90° and sending it north at 1.55 m/s. What is the angle that the velocity of the first ball makes after the collision, with respect to the east direction?
This problem is based on Law of Conservation of linear momentum. In an isolated system (no external force), the algebraic sum of momenta of bodies, along any straight line, remains constant and is not changed due to their mutual interactions.
In simpler terms, If the net external force acting on a system of bodies is zero, then the momentum of the system remains constant.
One must remember that the momentum of the system is conserved and not that of the individual particles. The momentum of the individual bodies in the system might increase or decrease , but the momentum of the system will always be conserved, as long as there is no external net force acting on it.
Solution