Laboratory equipment, namely, force tables for use in laboratories to determine the vector sum of different forces; torque tables for use in analyzing problems of torque and center of gravity; equilibrium cranes for use in illustrating that static equilibrium is achieved when both the forces and the moments are in equilibrium; mass hangers for hanging laboratory weights; air track substitutions, consisting of perforated triangular rails eimitting air for use in studying frictionless linear motion; air tables consisting of a mechanism of air levitated discs on a precisely flat table for studying motion in two dimensions; free fall devices, namely, laboratory test equipment to study the effect of gravity on a freely falling object; inertia wheels used in a laboratory to demonstrate the principles of angular acceleration under a constant torque and determine the effect of friction; harmonic oscillators; pendulum sets consisting of electronic sensors for sensing pendulums and pendulums sold as a unit; centripal force devices, namely, apparatus for the study and measurement of centripetal force, all used as laboratory equipment in an educational setting