Answer
$2.4\times 10^5N$
Work Step by Step
As $A=\pi Dh=\pi(4.8)(1.8)=27m^2$
Now $P=\rho g(\frac{1}{2}h)=(1000)(9.81)(0.90)=8.8KPa$
We can find the required force as
$F=PA$
We plug in the known values to obtain:
$F=(27)(8.8\times 10^3)=2.4\times 10^5N$
