OBJECT: To determine the values of the coefficient of kinetic friction and the coefficient of static friction for two particular surfaces.
METHOD: A loaded block is placed on a horizontal surface and the tractive force for each load, required to pull the block along the plane, is determined. These observations are plotted and the values of the coefficient of kinetic friction and the weight of the unloaded block are determined from the graph. The plane is then inclined so that the block slides down it without acceleration and the coefficient of kinetic friction redetermined from the angle the plane makes with the horizontal. The coefficient of static friction is determined in a similar manner. The block is placed on the plane, the plane is gradually elevated, the angle at which the block begins to slide is noted and this angle is used to determine the coefficient of static friction.
