please help with this

The container shown below contains water (w=1000kg/m3) and extends c=5m into the page. The top of the container is sealed shut by a massless gate angled at =45 to the horizontal. The water level in the container is b=1.5m above the hinge, as shown. Above the water in the container there is air at a pressure of 2atm (absolute). The air outside the container is at 1atm absolute pressure. The apex of the container is a=1m above the water surface. Determine the force, F, that must be applied perpendicular to the gate at the locatio