(a) it is known that the lip at a cannot withstand a (vertical) force greater than fm. derive an equation to calculate the maximum height of water in the reservoir (call it hm) which ensures that the force on the gate at a does not exceed the maximum. all equations used must be labeled/described in a few words. any symbol not given above must be de ned. (b) the manufacturer has speci ed fm = 400 kn. the hydraulic engineer wants to keep a 10% safety margin, hence the force at a cannot exceed 0: 9fm. calculate a numerical value for the maximum allowed water height in this case. assume = 1000 kg/m3, g = 9: 8 m/s2, b = 3 m, l = 4 m, w = 100 kn. (c) for the conditions in (b), will the force at the hinge exceed the maximum fm? show calculations to conclude yes or no.