Hey, while reading Kleppner & Kolenkow's discourse on gyrocompasses, I ran into a statement I could not wrap my head around: "The pivots at A and B allow the system to swing freely about the y axis, so there can be no torque along the y-axis." AB is an axis along the y-axis, which is the axis along which the gyrocompass can freely swing. The spin axis is along the x-axis. How can this be true? If the gyrocompass can swing along the y-axis from initially no angular velocity along the y-axis, it must have some torque to accelerate it, and hence torque along the y-axis. This seems extremely paradoxical to me. Can someone explain?