- A light elastic string has natural length \(a\) and modulus of elasticity 4 mg . One end of the string is attached to a fixed point \(A\) and a particle of mass \(m\) is attached to the other end.
The particle is released from rest at \(A\) and falls vertically until it comes to rest instantaneously at the point \(B\).
Find the distance \(A B\) in terms of \(a\).
(7 marks)