Final answer:
In a perfectly inelastic collision, the initial kinetic energy is always greater than the final kinetic energy because kinetic energy is not conserved, even though momentum is.
Step-by-step explanation:
When considering a perfectly inelastic collision, it's important to understand the conservation of momentum and changes in internal kinetic energy. In such a collision, the involved objects stick together and, in an extreme case, may even come to rest. According to the conservation of momentum, the final velocities can be calculated based on the initial velocities and masses. However, kinetic energy is not conserved in an inelastic collision. The collision is deemed perfectly inelastic when it minimizes the internal kinetic energy while still preserving momentum. Consequently, in a perfectly inelastic collision, the initial kinetic energy of the objects is greater than the final kinetic energy of the objects.