Friction Lab report
Friction
Cynthia Clark
Student No. xxxxx
May 19, 2009
Abstract
This experiment measures the coefficient of static friction (μs) and kinetic friction (μk) between objects of different materials. Friction is a force that must be overcome before an object can move across a surface. A plain block of wood and a block of wood with sandpaper on one side and glass on the other were used. All of the blocks had a soup can with a mass of 0.41 kg placed on top in order to provide enough mass to allow readings to be taken. They were moved along a wood plank while being attached to a 500-g spring scale in order to record the values when a) the block first moved, representing μs and b) as it traveled at a constant speed, representing μk. In one experiment the wood block was placed on its side and the experiment repeated. Overall, the results showed that μs > μk, and that the block that had the least surface area on the plank also had lower coefficients of friction when compared to one with more surface area on the plank.
Introduction
The purpose of this experiment is to observe the friction force and to determine the coefficient of kinetic friction as well as static friction of materials of different roughness. Various types of materials were used, as well as horizontal versus inclined ramps.
Friction occurs when two surfaces come into contact. The rough areas of each surface can come into contact and become cold-welded. Before an object can move over a surface, these cold-welds must be broken. It is a non-conservative force; the force used to overcome the frictional force and allow an object to move is dissipated into heat energy and will not return to the system once the movement stops.
Specifically, this lab will calculate the coefficient of friction. Unlike most coefficients in Physics, friction behaves differently depending on whether the object is at rest or at motion.
Cynthia Clark
Student No. xxxxx
May 19, 2009
Abstract
This experiment measures the coefficient of static friction (μs) and kinetic friction (μk) between objects of different materials. Friction is a force that must be overcome before an object can move across a surface. A plain block of wood and a block of wood with sandpaper on one side and glass on the other were used. All of the blocks had a soup can with a mass of 0.41 kg placed on top in order to provide enough mass to allow readings to be taken. They were moved along a wood plank while being attached to a 500-g spring scale in order to record the values when a) the block first moved, representing μs and b) as it traveled at a constant speed, representing μk. In one experiment the wood block was placed on its side and the experiment repeated. Overall, the results showed that μs > μk, and that the block that had the least surface area on the plank also had lower coefficients of friction when compared to one with more surface area on the plank.
Introduction
The purpose of this experiment is to observe the friction force and to determine the coefficient of kinetic friction as well as static friction of materials of different roughness. Various types of materials were used, as well as horizontal versus inclined ramps.
Friction occurs when two surfaces come into contact. The rough areas of each surface can come into contact and become cold-welded. Before an object can move over a surface, these cold-welds must be broken. It is a non-conservative force; the force used to overcome the frictional force and allow an object to move is dissipated into heat energy and will not return to the system once the movement stops.
Specifically, this lab will calculate the coefficient of friction. Unlike most coefficients in Physics, friction behaves differently depending on whether the object is at rest or at motion.
References: Jeschofnig, PhD., P. (No Date). Physics I: Lab Manual of Experiments for the Independent Study of Physics. LabPaq. Nave, R. (No Date). Friction. Georgia State University. Retrieved on May 19, 2009, from http://hyperphysics.phy-astr.gsu.edu/hbase/frict.html. Serway, R. (1994). Principles of Physics. Fort Worth, TX: Saunders College Publishing Harcourt Brace College Publishers. Singh, S. K. (2007). Induced motion on a rough inclined plane. Connexions. Retrieved May 19, 2009, from http://cnx.org/content/m14077/latest/.