The slender ladder has a mass of 10 kg. It is released from rest in the position shown. Friction at the two contact surfaces are negligible. Determine the angular acceleration of the ladder. I summed forces in the x,y direction, summed moments about the ladder's center of mass, wrote a kinematics equation relating the angular acceleration to the acceleration of its center of mass for a total of 5 unknowns (Force at bottom, ax, ay, angular acceleration, force at the vertical wall) and 5 equations. I have angular acceleration = 3.75 rad/s^2. This was on a multiple choice test, but there was no answer of 3.75 rad/s^2. I've been at this problem for days, making the same "mistake" over and over. I have found that the solutions manual of a similar problem is also doing the same thing I'm doing. Did my professor make a mistake?