Physics Study Guide/Periodic Motion
is the spring constant and is the displacement (the force is the restoring force)
For this equation to be approximately accurate, needs to be below the spring's elastic limit. If is more than the spring's elastic limit, the spring will exhibit "plastic behaviour" meaning that it will not return to its original position.
potential energy stored in a compressed recoiled spring
is the period, is the mass, and is the spring constant.