A simple pendulum consists of a mass suspended from a string or rod of negligible mass that oscillates due to gravity. It exhibits simple harmonic motion that can be modeled by equations relating the period of oscillation to the length of the pendulum. When displaced from its resting position, the pendulum experiences a restoring force towards the center due to gravity. Sample problems are provided to help understand how simple pendulums work based on conservation of energy and modeling their motion with graphs of position, velocity and acceleration over time.