This simple device is a must-have for teaching a class about friction. It provides an ideal device for demonstration showing resolution of forces, acceleration down a plane, work, potential energy, and friction. The unit is made of smooth wood with a metal pulley attached to the incline and a large protractor for accurately recording the angle of incline. Three different-sized boards with eye hooks are also included for study of how displacement, surface contact, and weight affect frictional forces. Instructions are provided. Stand not included.