A mass-spring system consists of a mass attached to a spring, which can stretch or compress. When the mass is displaced from its equilibrium position, the spring exerts a restoring force that tries to bring the mass back to its original position. This system is a classic example of simple harmonic motion, where the mass oscillates back and forth around the equilibrium point. The behavior of a mass-spring system can be described using Hooke's Law, which states that the force exerted by the spring is proportional to the displacement. The system's oscillation frequency depends on the mass and the spring constant, a measure of the spring's stiffness. This concept is widely used in physics and engineering to analyze vibrations and mechanical systems.