The triangular gate CDE is hinged along $CD$ and is opened by a normal force $P$ applied at E$.$ It holds water above it and is open to the atmosphere on its lower side. Neglecting the weight of the gate, find $($a$)$ the magnitude of force exerted on the gate; $($b$)$ the location of pressure center; $($c$)$ the force P needed to open the gate. $($Hint$,x=0$ and $y=8$ at $C,=9\mathrm{.}81{10}^3\frac{N}{m^2})$