A barrel will rupture when the gauge pressure within it reaches $350 \mathrm{kPa}$. It is attached to the lower end of a vertical pipe, with the pipe and barrel filled with oil $\left(\rho=890 \mathrm{~kg} / \mathrm{m}^{3}\right)$. How long can the pipe be if the barrel is not to rupture?
From $P=\rho g h$ we have
$$
h=\frac{P}{\rho g}=\frac{350 \times 10^{3} \mathrm{~N} / \mathrm{m}^{2}}{\left(9.81 \mathrm{~m} / \mathrm{s}^{2}\right)\left(890 \mathrm{~kg} / \mathrm{m}^{3}\right)}=40.1 \mathrm{~m}
$$