This apparatus is used to measure the co-efficient of friction of different materials at different angles. The friction increases due to the roughness of surfaces. The unit consists of a plane surface which has a pulley at its one end. The plane can be set to any angle with the help of pointer and protector. Blocks of different materials are available with this apparatus. A cord is tied to the block and at the other end of cord, a hanger is tied. The cord is passed over the pulley and weights are placed in the hanger so that the block starts moving.
Friction experiments on the inclined plane help students to understand the fundamentals of mechanical friction. The main elements of FF-1109 are a sliding surface (the inclined plane), with an adjustable angle of inclination, and four samples. A sample is moved from the stationary state to the sliding state in two ways. In the first experiment, the plane is carefully tilted until the sample begins to slide downwards and the downward force is greater than the static friction force.
In the second experiment, a weight acts as a tensile force upon the sample. The weight is gradually in creased until the sample begins to slide up wards in a uniform motion. The angle of inclination of the plane is not altered in this experiment.