Chapter 12. Measurement of Force
C.S. Bahra and J. Paros
12.1. Basic Concepts
If a body is released, it will start to fall with an acceleration due to gravity or acceleration of free fall of its location. We denote by g the resultant acceleration due to attraction of the earth on the body and the component of acceleration due to rotation of the earth about its axis. The value of g varies with location and height, and this variation is about 0.5 percent between the equator and the poles. The approximate value of g is 9.81 m/s 2. A knowledge of the precise value of g is necessary to determine gravitational forces acting on known masses at rest, relative to the surface of the earth, in order to establish practical standards of force. Practical standards ...