American Journal of Physics vol:68 issue:8 pages:704-711
A rod, connected with a horizontal hinge to the vertical axle of a motor, will deviate from the vertical at angular frequencies of the motor above a certain minimum value. The acceleration of gravity is related in a simple way to the speed of the motor, the length of the rod, and its angle with the vertical. It turns out that g can be measured in this way with an accuracy of about 0.1% without the use of sophisticated technology or the application of corrections to the result. The system has some other interesting features which make it particularly appropriate for the undergraduate laboratory. (C) 2000 American Accociation of Physics Teachers.