Simple Harmonic Motion

A light spring is suspended with mass \(m_1\) at its lower end and its upper end fixed to a rigid support. The mass is pulled down a short distance and then released. The period of oscillation is \(T\) second. When a mass \(m_2\) is added to \(m_1\) and the system is made to oscillate, the period is found to be \(\frac{3}{2} T\). The ratio \(m_1: m_2\) is