Final answer:
A perfectly elastic collision conserves momentum and impulse.
Step-by-step explanation:
The conservation of momentum and impulse is applicable in a perfectly elastic collision.
Momentum is defined as the product of an object's mass and velocity, and impulse is the change in momentum. According to the impulse-momentum theorem, the change in momentum of a system is equal to the impulse applied to the system.
In a perfectly elastic collision, both momentum and kinetic energy are conserved. This means that the total momentum before the collision is equal to the total momentum after the collision, and the total impulse applied to the system is zero.