The gate is $1\mathrm{.}2m$ wide, hinged at point $B,$ and rests against a smooth wall at A$.$ Compute $($a$)$ the force on the gate due to sea water pressure, $($b$)$ the horizontal force exerted by the wall at point $A,$ and $($c$)$ the reaction at hinge $B.$

The tank in the fig. contains oil $($sp gr $=0\mathrm{.}8)$ and water as shown. Find the resultant force on side ABC and its point of application. ABC is $1\mathrm{.}2m$ wide