Figure:
a) CASE A ##\rightarrow p_a=101300\, \textrm{Pa}##
$$F_{\textrm{res}}?,\,\, y_c-y_{cg}=y_{cp}$$
We find ##h_{cg}\rightarrow h_{cg}=3+h##
$$h=0,75\cdot \sin (30)=0,375\, \textrm{m}\rightarrow h_{cg}=3,375\, \textrm{m}$$
$$p_{cG}=\rho_{H2O}gh_{cg}=33108,75\, \textrm{Pa}$$
We calculate...