In a perfectly inelastic collision, the total momentum of the system ___ (i) ___ constant, while the total kinetic energy of the system___ (ii) ___constant.

(i) Momentum of the system is constant

(ii) Total kinetic energy of the system is not constant.

Explanation:

In perfectly inelastic collision, the total momentum of the system is constant while the the total kinetic energy of the system is not constant. The total; kinetic energy is not constant because some of the energy is lost in the process of collision. In this case, two bodies sticks together and both will move with a constant velocity. Also, the coefficient of restitution is equal to 0.