$${p_1 = p_0 - \frac{1}{2} (1,21\, \mathrm{kg/m^3})(27,25\, \mathrm{m/s})^2 \left( \frac{(0,0330\, \mathrm{m^2})^2}{(0,0310\, \mathrm{m^2})^2} -1 \right) \\ = p_0 - 59,838\, \mathrm{Pa} \approx \underline{\underline{p_0 - 59,8\, \mathrm{Pa}}}}$$