A force table is a simple physics lab apparatus that demonstrates the concept of addition of forces on a two-dimensional field. Also called a force board, the force table allows users to calculate the sum of vector forces from weighted chains that pull a central ring.
The force table is composed of a circular ring attached to chains or strings from which weights may be dangled. The ring and attached strings are suspended over a protractor disk that measures the angle of the strings. To use the force table in a physics experiment, weights are attached to three or more strings connected to the ring. As each weight is applied, the string pulls the ring towards its side. When another weight is placed on a separate string on the opposite side, it will also pull the central ring towards its direction. This creates a state of tug-of-war between the weights as the ring tries to balance the opposing forces. The objective of this experiment is to align the ring at the exact center of the force table, because it is only at this orientation that the forces are in equilibrium.
Using the force table enables the user to understand the concept of vector summation of forces, with consideration of the force's magnitude and direction. A state of equilibrium is achieved when the summation of all two-dimensional forces is equal to zero.