Mechanics is the branch of Physics dealing with the study of motion. It is the science which deals with the physical state of rest or motion of bodies under the action of the forces. The major division of the mechanics discipline separates classical mechanics from quantum mechanics.
In this set-up, the angular acceleration of a beam containing two small lead balls is measured by an interface system that contains an integrated capacitive sensor. This angular deflection results from the gravitational attraction of two large lead balls held on a swivel arm onto the small lead balls on the beam. The beam containing the two small lead balls is held suspended by a thin tungsten thread. So when the larger balls are brought near to the smaller balls, the tungsten thread oscillates about its equilibrium position due to the restoring moment of rotation generated in the thread. The measurements can be monitored on a computer.
This instrument allows measuring G with a high precision (with a maximum error of 15%). In the initial displacement method, G is derived from the angular acceleration of the balance due to movement of the attracting masses from one side to the other. The equilibrium displacement method derives G from the change in the equilibrium position of the balance at rest due to the change in position of the large masses. The built-in oil damping system reduces the time needed for equilibrium.