Solució: \begin{align} ∑ F = ma = 0 &= \cssId{Step1}{F + F_C·sinφ + F_B·sinφ + mg} \\[3px] &\cssId{Step2}{F + F_C·sinφ - F_C·sinφ + mg = 0} \\[3px] &\cssId{Step3}{F + mg = 0} \\[3px] &\cssId{Step4}{F = -mg} \\[3px] &\cssId{Step5}{NOTA:~Recordem~que~l'acceleració~és~-9,81~N/kg} \\[3px] \end{align}