Generally, the torque is defined as a force rotating a lever (IP leg) about its pivot (flexure). Thus, using the simplified model of the IP, as shown in figure 4.2a, the force, F , applied perpendicular to the IP leg with length L l , bends the flexure. The tip of the leg is displaced by x . Since the force acts normal to the leg at radial distance, L l , from the pivot, the torque on the flexure is given as: