In an elastic collision, which quantities are conserved?

In an elastic collision, which quantities are conserved?

• A. Both Kinetic Energy and Momentum are conserved
• B. Only Kinetic Energy is conserved
• C. Only Momentum is conserved
• D. Neither Kinetic Energy nor Momentum is conserved

Answer: (A)

In an elastic collision, the interaction forces are conservative and no kinetic energy is lost to deformation, heat, or sound. That means the total momentum of the system stays the same because there are no external impulses, and the total kinetic energy also stays the same because all the energy involved in the motion is recovered after the collision. So both quantities are conserved: the momentum before and after remains equal, and the total kinetic energy before and after remains equal. This is why this option is the best choice. To keep the idea clear, remember that momentum conservation applies to any collision in an isolated system, while kinetic energy conservation is specific to elastic collisions. In inelastic collisions, momentum is still conserved, but some kinetic energy is transformed into other forms and is not recovered as motion.

In an elastic collision, the interaction forces are conservative and no kinetic energy is lost to deformation, heat, or sound. That means the total momentum of the system stays the same because there are no external impulses, and the total kinetic energy also stays the same because all the energy involved in the motion is recovered after the collision. So both quantities are conserved: the momentum before and after remains equal, and the total kinetic energy before and after remains equal. This is why this option is the best choice.

To keep the idea clear, remember that momentum conservation applies to any collision in an isolated system, while kinetic energy conservation is specific to elastic collisions. In inelastic collisions, momentum is still conserved, but some kinetic energy is transformed into other forms and is not recovered as motion.