A Comparison of the Kinetic and Static Friction - Essay Example

From the graph, the greatest peak represents the motion, the instant when the block begins to move. The necessary force to keep the block in motion equals the kinetic force which is less than the static force needed to cause the block to move hence the value of the Static friction coefficient is 0.04 while the value of the Kinetic friction coefficient is 0.14.

A hanging mass without any weight attached to the pulley shows no motion of the box. With the gradual addition of weight on the hanging mass, the box begins to move hence overcoming static friction force. The force at which the box begins to move represents the static force since it is the force causing the box just to move.

During motion, the frictional force attained helps maintain the box in motion as it also increases proportionally with the increase in the hanging mass until the motion gains a constant rate. The static coefficient of friction is a result of the required force to cause an object to start moving. As soon as the object starts to slide at a constant rate, the coefficient of kinetic friction is then the required force to retain the object in motion (Matolyak and Ajawad 35-37). In this setup, the factor of gravitational force causing the object to just set motion is the same as the resistive force that keeps the object at rest.

This is then the static friction force. An increase in the inclination angle decreases the gravitational force acting on the box. An inclination of 10 degrees overcomes the resistive force causing the box just to move and a further inclination of 9.2 degrees keeps the box in motion hence providing for the kinetic friction force. The actual coefficient of static friction of wood is 0.25-0.5 and the coefficient of kinetic friction of wood is 0.2. Out of the three methods used, method 2 was the most precise since the coefficient of static friction was 0. 349 lies averagely within the actual range and its coefficient of kinetic friction 0.232 is closer to the actual range values. 

The string is not absolutely parallel to the working bench causing tension forces and calculating of kinetic friction without including the mass of the box and acceleration due to the acute angle.

            To improve the experiment, ensure that the string is perfectly set straight with the working bench and the pulley system. Ensure that the hanging masses have no motion before the addition of any extra masses. The mass of the box and acceleration should be included when determining the kinetic friction force.

                Sports shoes require enough friction to be between the shoe sole and the surface or tract of racing in order to ensure the stability of the runner. When the shoe sole and the tract surface are in contact frictional force will determine how swift the movement of the runner will be. The coefficient of static friction will determine the overall horizontal force required to cause ease of movement while a coefficient of kinetic friction is the overall moment to cause rotation on the surface. Shoes will a high static frictional force helps to reduce the sliding effect same as in car tires whereby effective tire treads require high static force to initiate motion and less kinetic force to maintain the motion.