FIGURE P$2\mathrm{.}6\mathrm{.}17$

$5.$ Prob. $2\mathrm{.}8\mathrm{.}7$ p$.$ IP$-19[$Ans: $889$ N$].$

$2\mathrm{.}8\mathrm{.}7$ WP A piston having a cross$-$sectional area of $0\mathrm{.}07m^2$ is located in a cylinder containing water, as shown in Fig. P$2\mathrm{.}8\mathrm{.}7.$ An open U$-$tube manometer is connected to the cylinder as shown. For $h_1=60mm$ and $h=100mm,$ what is the value of the applied force, $P,$ acting on the piston? The weight of the piston is negligible.

FIGURE P$2\mathrm{.}8\mathrm{.}7$