$(1)$
\[
h_G= y_G\sin\theta= 1.5\sin60^\circ\\
A=\frac{\pi}{4}d^2=\frac{\pi}{4}
\]
\[
\begin{align}
F=\rho g h_G A
&=1000\times 9.8\times \frac{\pi}{4} \times 1.5\sin60^\circ\\
&=9998.57\\
&=10.0 \,\rm{ kN}
\end{align}\]
$(2)$
\[\begin{align}
I_G
=\frac{\pi d^4}{64}&=0.049087\\
&=0.0491 \,\rm{ m^4}
\end{align}\]
$(3)$
\[\begin{align}
h_C=\left(y_G+\frac{I_G}{y_G A}\right)\sin\theta
&=\left(1.5+\frac{0.04909}{1.5\times \frac{\pi}{4}}\right)\sin60^\circ\\
&=1.335\\
&=1.34 \,\rm{ m}
\end{align}\]