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 mass-spring systems can be described using Hooke's Law, which states that the force exerted by the spring is proportional to its displacement. These systems are commonly studied in physics and engineering to understand oscillations, vibrations, and energy transfer, making them essential in various applications, including mechanical engineering and seismology.