A light elastic string, of natural length \(3a\) and modulus of elasticity \(6mg\), has one end attached to a fixed point \(A\). A particle \(P\) of mass \(2m\) is attached to the other end of the string and hangs in equilibrium at the point \(O\), vertically below \(A\).
- Find the distance \(AO\). [3]
The particle is now raised to point \(C\) vertically below \(A\), where \(AC > 3a\), and is released from rest.
- Show that \(P\) moves with simple harmonic motion of period \(2\pi\sqrt{\frac{a}{g}}\). [5]
It is given that \(OC = \frac{1}{4}a\).
- Find the greatest speed of \(P\) during the motion. [3]
The point \(D\) is vertically above \(O\) and \(OD = \frac{1}{8}a\). The string is cut as \(P\) passes through \(D\), moving upwards.
- Find the greatest height of \(P\) above \(O\) in the subsequent motion. [4]