(b) Each of the four uniform movable bars in the (linkage) mechanism given in Figure 2b has a mass m. The equilibrium position of the linkage in the vertical plane is controlled by the force P applied to the end of the lower bar, as shown. For a given value of P, determine the equilibrium angle (by applying virtual work principle. Is it possible for the equilibrium position shown to be maintained by replacing the force P by a moment M applied to the end of the lower horizontal bar? Justify your answer.