We present results of ten years of measurements of the gravitational constant made using an evacuated torsion balance. We obtained the value G = (6.6729 + 0.0005).10 -11 N.m2.kg -2. We have detenninea the major destabilizing factors accompanying the measurement process and have estimated the contribution from different sources of error.Method for Determln~tlon of G. We present the results of determination of the gravitational constant G using a torsion balance [1][2][3][4]. In the gravitational field of a stationary spherical attracting mass, the equation of motion of the balance has the form [5]:
~ I dt = + =z 9 + GM [rnlL ~ (b t + bz) sin ~p + +m 2 (b~ + b,) 1 2si n q~] / J =0,,p is the angle of deviation of the balance rod from the equilibrium position, G is the gravitational constant; M is the difference between the masses of the attracting sphere and the air displaced by it; m 1 is the mass of the weight on the balance rod; m 2 is the mass of the balance rod;/-5, L6, Li are the distances from the axis of rotation to the center of mass of the weight on the balance rod, the ends of the balance rod, and the center of mass of the attracting sphere; the subscript i indicates the position of the sphere; b 2 and b 4 are obtained from b I and b 3 by changing the sign in front of L 5 and L6; oJ is the cyclic vibrational frequency of the balance in the absence of attracting masses; J is the moment of inertia of the torsion body relative to the vertical axis of rotation. After expanding the functions of the moments of the attractive forces in a series in odd powers of ~ and using the theory of small anharmonic oscillations, for calculating G we obtain a system of difference equations:(2) where b i = bti + b2i + b3i + b4i,
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