Practise Edexcel A-Level Physics simple harmonic motion conditions by identifying proportional restoring force and displacement from equilibrium.
The photograph shows the 60-storey John Hancock Tower in Boston. This is the tallest building in the state of Massachusetts in the USA.
Shortly after the building was completed in 1976 it was discovered that the wind caused the building to have large amplitude oscillations. To reduce the amplitude, a damper system was installed on the 58th floor.
The damper system consists of a lead box supported between springs, as shown below.
When the lead box is displaced, it moves with damped simple harmonic motion.
State what is meant by simple harmonic motion.