Simple Harmonic Motion

A

Mass Suppose the mass is initially at A and that after a time t it is at B. During this time the radius r of the circle sweeps through an angle θ. The motion of the mass from A round the circle is equivalent to the motion of a mass from A to C and then back to A. The distance X is the displacement of the mass from the centre of motion at any time t. The distance OB ( r ) is the amplitude of motion.