(a)[1]
State the principle of moments.
(b(i))[2]
Apply the principle of moments to demonstrate that the upthrust $U$ produced by the water on the cylinder is $1.4\,\text{N}$.
(b(ii))[3]
The water has density $1.0 \times 10^{3}\,\text{kg m}^{-3}$. Calculate the area $A$ of the circular cross-section of the cylinder.
(c)[3]
More water is slowly poured into the container in (b), so the depth $h$ in Fig. 3.1 rises steadily. The length $x$ is adjusted continuously so that the system stays in equilibrium. On Fig. 3.2, sketch how $x$ changes with $h$. Use the space below for any working.