In this experiment, we will investigate some of the principles of friction, such as: 1. The coefficient of static friction, is usually greater than the coefficient of kinetic s, friction, k. 2.The frictional force, f, is proportional to the normal force, FN. 3. Friction always acts in a direction opposite to the motion of an object. SUPPLIES & EQUIPMENT: Friction board Friction Block Meter stick String & scissors Inclinometer Metric ruler Electronic balance Masking tape Clamp & rod for inclined plane Slotted masses Spirit Clamp-on pulley PROCEDURE: COEFFICIENT OF STATIC FRICTION We will determine the coefficient of static friction by tilting the board at an angle. At the point where the angle is just enough to cause the block to slip (overcome friction), we have: = f / FN s Fig.1: Experimental setup for Part A = 0: f + (-mg sin = 0 Fx with associated forces shown f = mg sin = 0: FN + (-mg cos = 0 Fy FN = mg cos = s = tan s 1. Place the block at the top of the inclined board. Experimentally determine the angle at which the block just breaks loose and starts sliding down the incline, using an inclinometer. 2. Repeat step 1-A five times and calculate an average value for the angle and then , s calculate the coefficient of static friction = tangent  B. COEFFICIENT OF KINETIC FRICTION The coefficient of kinetic friction will be determined by making use of the fact that the frictional force is proportional to the normal force, f = . kFN Fig. 2. Experimental setup for Part B with associated forces
In this experiment, we will investigate some of the principles of friction, such as: 1. The coefficient of static friction, s, is usually greater than the coefficient of kinetic friction, k. 2.The frictional force, f, is proportional to the normal force, FN. 3. Friction always acts in a direction opposite to the motion of an object. SUPPLIES & EQUIPMENT: Friction board Friction Block Meter stick String & scissors Inclinometer Metric ruler Electronic balance Masking tape Clamp & rod for inclined plane Slotted masses Spirit Clamp-on pulley PROCEDURE: COEFFICIENT OF STATIC FRICTION We will determine the coefficient of static friction by tilting the board at an angle. At the point where the angle is just enough to cause the block to slip (overcome friction), we have: Fig.1: Experimental setup for Part A with associated forces shown s = f / FN Fx = 0: f + (-mg sin = 0 f = mg sin Fy = 0: FN + (-mg cos = 0 FN = mg cos s = s = tan 1. Place the block at the top of the inclined board. Experimentally determine the angle at which the block just breaks loose and starts sliding down the incline, using an inclinometer. 2. Repeat step 1-A five times and calculate an average value for the angle , and then calculate the coefficient of static friction s = tangent  B. COEFFICIENT OF KINETIC FRICTION The coefficient of kinetic friction will be determined by making use of the fact that the frictional force is proportional to the normal force, f = kFN . Fig. 2. Experimental setup for Part B with associated forces