Afreshwater marsh is drained to the ocean through anautomatic
tide gate that is 4ft wide and 3ft high. the gate is heldby hinges
located along its top edge at a and bears on a sill at b. at a given
time, the water levels in the marsh and in the ocean areh = 6 feet
and d = 9 ft, respectively. determine the force exertedby the sill
on the gate at b and the hinger reaction at a. (specific weight of
salt water = 64lb / ft 3 ).