b$)$ A lock on a canal is sealed by a gate that is $4\mathrm{.}0m$ long. The gate is perpendicular

to the sides of the lock. When the lock is used there is water on one side of the gate

to a depth of $5\mathrm{.}0m,$ and $3\mathrm{.}0m$ on the other side $($as shown in Figure Q$1$b$).$

Accept water of density $1000k\frac{g}{m^3}.$

i$)$ What is the hydrostatic force magnitude on the two sides of the gate? $(3$ marks$)$

ii$)$ At what height from bed $Y1,Y2$ do the two forces act?

$(3$ marks$)$

iii$)$ What is the magnitude of the overall resultant hydrostatic force on the gate and

at what height from the bed $Y_R$ does it act?

$(3$ marks$)$

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Figure Q$1$b: Gate for question $1$b