it may seem counterintuitive that the three collisions can have such ditterent outcomes. However, the different types of balls lead to different types of collisions. For this reason, we classify collisions based on their outcomes. For example, a collision like the one between Sticker and its target, in which the colliding bodies move together as a unit after the collision, is known as perfectly inelastic. The classification of collisions depends on the extent to which the kinetic energy of the system is the same before and after the collision. If the kinetic energy is exactly the same before and after, the collision is perfectly elastic. In most collisions, some kinetic energy is lost (this energy is transformed to some other form of energy, like the internal thermal energy of one of the balls), and the collision is inelastic. Consider the collisions above, with Sticker, Stopper, Bouncer, and their respective targets. For each, state whether the momentum of the ball-target system is or is not conserved, and whether it's possible that the kinetic energy of that system is the same before and after. Sticker and its target: The momentum will remain conserved and the kinetic energy before and after the collision will not be the same Stopper and its target: The momentum will remain conserved. the kinetic energy before and after the collision will not be the same Bouncer and its target: The momentum will remain conserved the kinetic energy before and after the collision will be the same