a common physics problem and the archetype of the system for simple harmonic motion. In its classic form, the mass on a spring consists of a mass attached to a massless and ideal Hooke's Law spring (for which the restoring force is linearly proportional to the spring displacement from its equilibrium position).
The classic case considers a mass resting on a frictionless surface, moving horizontally, as in the worked Example Mass Between Two Springs, but the situation is equivalent for a mass hanging from a vertical spring, as we demonstrate in the Worked Example Mass on a Vertical Spring.