The Three Dimensional Equilibrium equipment is used for studying the equilibrium of five concurrent and non-concurrent forces in a three dimensional system. A vertical load with a cord is applied at one of the joints. Each cord is marked out a 100 mm length. Two mirrors are attached on two adjacent side walls and transparent plates with transparent graph grids are attached on the other two side walls. Four cords, each with a load hanger outside the frame, pass over the pulleys and meet inside the frame concurrently or non-concurrently with an additional cord between two joints. By aligning each marked cord to the mirror, its coordinates in space can be measured. A rigid box frame has four swiveling pulleys at the top corners and leveling screws at the legs.
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