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