A simple pendulum is a mass (called the bob) attached to a string or rod of fixed length, which is free to swing back and forth under the influence of gravity.
Related terms
Amplitude: The maximum displacement from equilibrium position in a pendulum's oscillation.
Frequency: The number of complete oscillations (back-and-forth swings) made by a pendulum per unit time.
Length: The distance between the point of suspension and the center of mass of the pendulum's bob.