Friction

Abstract

This chapter presents the concept of friction. When an object, such as a block of wood, is placed on floor and sufficient force is applied to the block, the force being parallel to the floor, the block slides across the floor. When the force is removed, motion of the block stops; thus, there is a force that resists sliding. This force is called dynamic or sliding friction. A force may be applied to the block that is insufficient to move it. In this case, the force resisting motion is called the static friction or striction. Thus, there are two categories into which a frictional force may be split: (1) dynamic or sliding friction force that occurs when motion is taking place; and (2) static friction force that occurs before motion takes place. The size of the frictional force depends on the type of surface. The size of the frictional force depends on the size of the force acting at right angles to the surfaces in contact, called the normal force.