A child of mass 25kg sits on a simple swing of effective length 2.0m. The swing is pulled aside until the seat is 0.25m horizontally away from its mean position and then released from rest.
(i) Draw a neat labelled diagram showing all the forces acting on the child at the extreme position.
(ii) Explain, without using any calculations, why the subsequent motion of the swing can be regarded as simple harmonic for small angular displacements.
(iii) State clearly how the direction of the restoring force changes as the child moves from one extreme position through the mean position to the opposite extreme.
(iv) What change, if any, would occur in the nature of the motion if the swing were released from a much larger angular displacement? Give reasons for your answer.