We report two experiments which test the inverse-square distance dependence of the Newtonian gravitational force law. One experiment uses a torsion balance consisting of a 60-cm-long copper bar suspended at its midpoint by a tungsten wire, to compare the torque produced by copper masses 105 cm from the balance axis with the torque produced by a copper mass 5 cm from the side of the balance bar, near its end. Defining R₄ₗₓ to be the measured ratio of the torques due to the masses at 105 cm and 5 cm, and R₍₄ₖₓ₎₍ to be the corresponding ratio computed assuming an inverse-square force law, we find (R₄ₗₓ/R₍₄ₖₓ₎₍-1) = (1. 2 7) 10^-4. Assuming a force deviating from an inverse-square distance dependence by a factor 1+ lnr (cm), this result implies = (0. 5 2. 7) 10^-4. An earlier experiment, which has been reported previously, is described here in detail. This experiment tested the inverse-square law over a distance range of approximately 2 to 5 cm, by probing the gravitational field inside a steel mass tube using a copper test mass suspended from the end of a torsion balance bar. This experiment yielded a value for the parameter defined above: = (17) 10^-5. The results of both of these experiments are in good agreement with the Newton- ian prediction. Limits on the strength and range of a Yukawa potential term superimposed on the Newtonian gravitational potential are discussed.
Hoskins et al. (Sun,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: