Common examples of simple harmonic motion include an object attached to a spring, a swinging pendulum and loudspeakers. Simple harmonic motion refers to the swinging motion exhibited by any object in the presence of Hooke's law force and absence of frictional force.
In physics, periodic motion pertains to cyclical movement that repeats within a regular interval. When an inert object is disturbed, it tends to move in one direction or another, causing vibrations or oscillations. A type of periodic motion called simple harmonic motion is movement that experiences a restoring force that tends to return a moving object to its equilibrium state. When a spring is compressed or stretched, the restoring force is directly proportional to how far it was displaced. This phenomena obeys Hooke's law, which states that displacement increments or decrements with respect to the restoring force. An increase in displacement also increases the restoring force while a decrease in displacement also decreases the restoring force.
Simple harmonic motion is characterized by its amplitude, frequency and period. Amplitude refers to the farthest distance the object has traveled away from its equilibrium state. Frequency relates to the number of cycles the motion undergo in one second and the time interval between two cycles is known as the motion's period. The principle of simple harmonic motion is often used in making musical instruments.