ABSTRACT
When an object, such as a block of wood, is placed on a floor and sufficient force is applied to the block, the force being parallel to the floor, the block slides
When an object is placed on a flat surface and sufficient force is applied to the block, the force being parallel to the surface, the block slides across the surface. When the force is removed, motion of the block stops; thus there is a force which resists sliding. In this chapter, both dynamic and static frictions are explained, together with the factors that affect the size and direction of frictional forces. A low coefficient of friction is desirable in bearings, pistons moving within cylinders and on ski runs; however, for a force being transmitted by belt drives and braking systems, a high value of coefficient is necessary. Advantages and disadvantages of frictional forces are discussed and calculations are performed on friction on an inclined plane and screw jack efficiency.
