State, by reference to displacement, what is meant by simple harmonic motion.
A mass is undergoing oscillations in a vertical plane. The variation with displacement 
of the acceleration 
of the mass is shown in the figure below.
State two reasons why the motion of the mass is not simple harmonic.
A block of wood is floating in a liquid, as shown in the figure below.
The block is displaced vertically and then released. The variation with time 
of the displacement 
of the block from its equilibrium position is shown in the graph below.
Use data from the graph above to determine
the angular frequency 
of the oscillations,
the maximum vertical acceleration of the block.
.
.
