Final answer:
Yes, the work-energy theorem can be used to calculate the spring's velocity upon striking the ground because it relates work done to kinetic energy change, which in turn is related to velocity.
Step-by-step explanation:
The work-energy theorem is a fundamental principle in physics that relates the work done on an object to the change in its kinetic energy. This theorem can indeed be used to calculate the velocity of a spring when it strikes the ground, as long as the mass of the spring is constant and all forces acting on the spring (like gravity) are accounted for. Specifically, the work done by these forces as the spring moves is equal to the change in the spring's kinetic energy. Since kinetic energy is directly related to velocity (kinetic energy is ½ mass × velocity squared), calculating the change in kinetic energy between two points can give us information about the change in velocity, and thus the velocity upon impact.