Modified Cavendish Balance for Testing Gravitational Interior Solution
Richard Benish
In the hundreds of torsion balance experiments that have been performed for gravity research, the key data were obtained, typically, with the large and small masses in stationary positions and with the small masses staying outside the surfaces of the large masses. It remains to discover what happens when the balance arm has no restoring force to keep it in a stationary position and material has been removed from the large masses, so as to allow the small masses to move through them. This paper describes a new experiment whose purpose is to answer this question. We may thereby provide empirical support for a common problem in elementary physics: The ideal case involves a relatively isolated, uniformly dense spherical mass with a hole through a diameter. The problem is to find the pattern of motion that unfolds when a test mass is dropped into the hole. The well known theoretical answer is that the small mass undergoes simple harmonic motion. But nothing like this has ever been directly observed. With a suitably modified balance, I intend to demonstrate, as a first approximation, the correctness of the prediction that the small masses oscillate through the large masses.
