Redetermination of the Newtonian Gravitational ConstantG

Abstract

The universal Newtonian gravitational constant is being redetermined at the National Bureau of Standards with use of the method of Boyes in which the period of a torsion pendulum is altered by the presence of two 10.5-kg tungsten balls. The difference in the squares of the frequencies with and without the balls is proportional to $G$. The resulting value of $G$ is (6.6726\ifmmode\pm\else\textpm\fi{}0.0005)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}11}$ ${\mathrm{m}}^{3}$\ifmmode\cdot\else\textperiodcentered\fi{} ${\mathrm{sec}}^{\ensuremath{-}2}$\ifmmode\cdot\else\textperiodcentered\fi{} ${\mathrm{kg}}^{\ensuremath{-}1}$\ifmmode\cdot\else\textperiodcentered\fi{}