Spring pendulum

A spring pendulum is a physical system where a piece of mass is connected to a spring so that the resulting motion contains elements of a simple pendulum as well as a spring. The system is much more complex than a simple pendulum because the properties of the spring adds an extra dimension of freedom to the system. For example, when the spring compresses, the shorter radius causes the spring to move faster due to the conservation of angular momentum. Also there is the possibility that the spring has a range that is overtaken by the motion of the pendulum, making it practically neutral to the motion of the pendulum.