4.1
Determining Kinetic Coefficients of Friction
in Mechanical Systems
Observations and Data Collection
1. Complete the following Data Table
Data Table 1
Surface Description
Ivory-Colored Material
on Dry Metal
Mass of Sled
MS (kg)
Mass Added
M (kg)
0.250
0.500
0.750
White-Colored Material
on Dry Metal
0.250
0.500
0.750
Metal Material on Dry
Metal
0.250
0.500
0.750
Total Mass
MT (kg)
Weight of Sled and Mass
WT (Newtons)
Section 4.1
2. Complete the following Data Table
Data Table 2
Surface Description
Ivory-Colored
Material on Dry Metal
White-Colored
Material on Dry Metal
Metal Material on Dry
Metal
Kinetic Friction
Force
FKinetic
(Newtons)
Normal Force
(Newtons)
Coefficient of
Kinetic Friction
Average Coefficient of
Kinetic Friction
μK
μK
Section 4.1
Questions and Interpretations
1. Using the Coefficients of friction as a reference, rank the sleds from largest to
smallest coefficient of kinetic friction. (You may use data from classmates to
get a complete set of coefficients).
2. What impact did adding more normal force (N) for a given material have on the
coefficient of kinetic friction
μK, for a given material?
3. If you had to pull skids of material weighing 1000 pounds around in a
warehouse, from which material in this experiment would you make the skids?
Explain why.
4. Reflecting back on the lab, did it take (more, less, or the same amount) of force
to initiate movement as it did to maintain movement? Why?
5. Identify and list four real life situations where friction is desirable and four
where friction is undesirable.
Section 4.1
Notes