Related Experiment Video
Updated: Aug 29, 2026

Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
New measurements of G using the measurement standards laboratory torsion balance
T R Armstrong1, M P Fitzgerald
1Measurement Standard Laboratory of New Zealand, Industrial Research, P.O. Box 31-310 Lower Hutt, New Zealand. t.armstrong@irl.cri.nz
Abstract:
This Letter presents the results of a series of measurements of the Newtonian gravitational constant G using the compensated torsion balance developed at the Measurement Standards Laboratory. Since our last published result using the torsion balance in the compensated mode of operation [Meas. Sci. Technol. 10, 439 (1999)]], several improvements have been made to reduce the uncertainty in the final result. The new measurements have used both stainless steel and copper large masses. The values of G for the two sets of masses are in good agreement. After combining all of the measurements we get a value of G=6.673 87(0.000 27) x 10(-11) m3 kg(-1) s(-2). This new value is 5 parts in 10(5) smaller than our previous published values.
Related Concept Videos
Instrument Calibration
Analytical Balance Calibration
An analytical balance measures mass and requires regular calibration to...
Measurement: Standard Units
Measuring Acceleration Due to Gravity
A simple pendulum can be described as a point mass and a string. Meanwhile, a physical pendulum is any object whose oscillations are similar to a simple pendulum, but cannot be modeled as a point mass on a string because its mass is distributed over a larger area. The behavior of a physical pendulum can be modeled using the principles of...
Net Torque Calculations
Measurement: Derived Units
Rigid Body Equilibrium Problems - II
Consider two children sitting on a seesaw, which has negligible mass. The first child has a mass (m1) of 26 kg and sits at point A, which is 1.6 meters (r1) from the pivot point B; the second child has a mass (m2) of 32 kg and sits at point C. How far from the pivot point B should the second child sit (r2) to balance the seesaw?

