Consider the equilibrium of bar AB. The correct moment equation about point A should be A:SmA(F) = m + Psinq × L/2 + M + mA = 0 B:SmA(F) = -m – Psinq × L/2 + M = 0 C:SmA(F) = -mL – P × L/2 + M + mA = 0 D:SmA(F) = -m – Psinq × L/2 + M + mA = 0 答案: SmA(F) = -m – Psinq × L/2 + M + mA = 0