(a)[1]
State Hooke’s law in terms of extension and force.
(b)[2]
A spring is fixed to a support and hangs vertically, as shown in Fig. 6.1. An object M of mass $0.41\,\text{kg}$ is hung from the lower end of the spring. The spring stretches until M comes to rest at R. The spring constant is $25\,\text{N m}^{-1}$. Show that the spring’s extension is about $0.16\,\text{m}$.
(c(i))[1]
In Fig. 6.1, object M is pulled down an additional $0.060\,\text{m}$ to S and then let go. For M, at the instant of release, state the forces acting on M.
(c(ii))[3]
Calculate the acceleration of M from the forces acting on it.
(d)[2]
Describe and explain how the energy changes from the moment object $M$ in Fig. 6.1 is released until it first comes back to $R$.