$5\mathrm{.}2\mathrm{.}5$ Find the magnitude of the force, $F,$ required to hold the plate in Fig. P$5\mathrm{.}2\mathrm{.}5$ stationary$\mathrm{.}5\mathrm{.}2\mathrm{.}5$ Find the magnitude of the force, $F,$ required to hold the plate in Fig. P$5\mathrm{.}2\mathrm{.}5$ stationary.