(a)[2]
Define the moment of a force around a point in terms of its turning effect.
(b)
Fig. 3.1 shows one kind of balance used to measure mass.
(b(i))[2]
Show that the extension of the spring is about $1.3\,\text{mm}$.
(b(ii))[2]
Calculate the size of the moment about the pivot due to the object's weight.
(b(iii))[2]
Use your result from (b)(ii) to find the rise in tension in the spring caused by the $0.472\,\text{kg}$ mass.
(b(iv))[2]
Use the data in (b)(i) together with your answer in (b)(iii) to determine the spring constant $k$ for the spring. Include a unit in your answer.