Final answer:
In an inelastic collision, internal kinetic energy is not conserved; however, linear momentum and impulse are always conserved. The conservation of linear momentum is the key principle used to analyze the outcome of an inelastic collision.
Step-by-step explanation:
In an inelastic collision, kinetic energy is not conserved. However, linear momentum and impulse are conserved quantities in this type of collision. In an inelastic collision, such as when objects stick together, the final internal kinetic energy is less than the total internal kinetic energy before the collision. The impulse describes the change in momentum resulting from the average net external force applied during the time of collision.
According to Essential Knowledge 5.D.2, in any type of collision, linear momentum is conserved regardless of changes in kinetic energy. Therefore, when talking about an inelastic collision, it is the conservation of linear momentum that is relevant and should be considered to determine the final state of the system after the collision.