How is constant amplitude sustained in forced oscillations?

Video Transcript

This is College Physics Answers with Shaun Dychko. How is constant amplitude sustained in forced oscillations? Well this will only occur with damped forced oscillations; if you have forced oscillations in the presence of no damping then you have increasing amplitude as energy increases and increases due to the work being done by the force. So we are dealing with a damped oscillator and damping results in the loss of mechanical energy but the applied force does an amount of work on the oscillator to exactly compensate for the loss and this keeps the mechanical energy constant and therefore the amplitude constant.