Friction Coefficients essays

Friction Coefficients essays Determining the Coefficient of Friction This lab was meant to discover the most elementary and accurate way to determine kinetic and static friction between two surfaces. In our case, the two surfaces were a pine board and a polished aluminum ramp. We used gravity at a 45o angle and a stopwatch to determine the kinetic friction, and the angle of a ramp at which the board would start to slide for the static friction; understanding that certainly human error would become a factor. Friction is the resistive force acting between two bodies that in most cases inhibits motion. There are also two types of friction, static friction and kinetic friction. Static friction is the force needed to start a body, which is at rest, into motion. Kinetic friction is the retarding force acting upon a body already in motion. Friction, both static and kinetic, may be defined by the equation: f = Â µ n The assumptions we must make about friction are as follows: 1. The maximum friction force is proportional to the normal force 2. The maximum friction force is not proportional to the area of contact 3. The static friction force is always higher than the dynamic friction force 4. The kinetic friction force is independent of velocity Finding the coefficient of static friction To determine the coefficient of static friction begin by resting one end of our aluminum ramp on a ring stand and the other end on the ground. Then place the block of wood at the top of the ramp to see if it begins to slide at all. If the block of wood does not move increase the angle of the ramp by 5o and continue to do so until it does move as shown in Figure 1. When it starts to move decrease the angle by 1o increments until you find the angle at which it first begins to move. Measure that angle and use it in your calculations for static friction. Finding the coefficient of static friction ...