The Bifilar suspension system is one experimental technique to determine the moment of inertia of bar elements. The bar elements may be rectangular or cylindrical solid bars.
To find the moment of inertia of a respective solid object, two flexible strings were initially attached to the two ends of the bar and the other end fixed to the supporting frame. Make sure that the bar element and supports are parallel to each other. After determining the tensions in the flexible strings, the initial displacement was applied to the bar and allowed to oscillate a small amplitude from the static equilibrium position. By using the new position of the bar and determined the restoring torque and compared with accelerating torque. After calculating the radius of gyration and substituted in the moment of the inertia equation, determine the moment of inertia.