Final answer:
The kinetic energy of the teenager and the wheelchair can be different even if they have the same speed, due to the difference in their masses.
Step-by-step explanation:
Kinetic energy is proportional to speed squared, which means that even though the teenager and the wheelchair have the same speed, they don't necessarily have the same kinetic energy. The kinetic energy of an object also depends on its mass. If the teenager and the wheelchair have different masses, then their kinetic energies will be different even if they have the same speed. For example, if the teenager has a greater mass than the wheelchair, they will have a greater kinetic energy even if they have the same speed.