A weight W is suspended from a rigid support by a hard spring with stiffness constant 'K'. The spring is allowed to have only vertical motion. A simple pendulum of length 'l' with a bob of mass 'm' (mg<<W) is suspended from the weight W and is set oscillating in a horizontal direction. After sometime, the spring is observed to be exhibiting vertical oscillations of high amplitude. Are the 'Spring system' and 'Pendulum system' oscillating with the same frequency? And what should be the function 'f', if K=f(W,l)?