1. The problem statement, all variables and given/known data A rotational axis is directed perpendicular to the plane of a square and is located as shown in the drawing. Two forces, F1 and F2, are applied to diagonally opposite corners, and act along the sides of the square, first as shown in part a and then as shown in part b of the drawing. In each case the net torque produced by the forces is zero. The square is one meter on a side, and the magnitude of F2 is three times that of F1. Find the distances a and b that locate the axis. 2. Relevant equations Torque = r x F |Torque| = |r| |F| sin(angle) 3. The attempt at a solution I first tried to attempt this by setting up equations for the net torque of both cases. I realized that the net torque would have to be zero and I knew the forces, but I incorrectly thought that the distance from the force to the axis (or as the textbook likes to call it, the lever arm) is some hypotenuse of a triangle whose legs are somewhere along the sides of the square. As I tried to solve the problem and find the angle between the displacement and the force, I realized that I had too many unknown variables. I then looked at my solution guide, and it stated that the "lever arm"s are actually a and b themselves, and the angles between the forces and the lever arms are both just 90 degrees. With this information, I attempted the problem once again and solved it with ease: (F2) =(3F1) (F1)(b)-(F2)(a) = 0 -----> (F1)(b) = (F2)(a) ------> (F1)(b) = (3F1)(a) ------> b = 3a (F1)(1-a) -(F2)(b) = 0 -----> (F1)(1-a) = (F2)(b) -----> (F1)(1-a) = (3F1)(b) -----> 1-a = 3b System of equations: 1-a = 3b b = 3a 1-a = 3(3a) -----> 1-a = 9a -----> 10a = 1 -----> a = 0.1m b = 3(0.1) -----> b = 0.3m Still, I am really really confused about why a and b are the distances between the force and the axis. The forces act at the corners, so shouldn't the distances between the force and the axis be the distance of a line from the corner to the axis?