Consider a beam with an applied vertical force, F, a couple moment, M, that is restrained at point A by a pin joint and at point B by a roller. F M In the free-body diagram of the beam shown here, F A, M B. y Ay, Az, and By are the supports' reaction forces. If the beam is subjected to a hypothetical translation in the y direction, y, what is the virtual work, U, done on the beam in terms of some of or all of the variables A,, Az, By, F. M, and dy? F A dy Express your answer in terms of some or all of the variables Ay, Az, By, F, M, and dy.