graph corresponding to the block at rest, the time when the block just started to move, and
the time when the block was moving at constant speed.
2.
The
coefficient of friction
is a constant that relates the normal force between two objects
(blocks and table) and the force of friction. Based on your graph (Run 1) from Part I, would
you expect the coefficient of static friction to be greater than, less than, or the same as the
coefficient of kinetic friction.
3.
Plot a graph of the maximum static friction force (vertical
axis)
vs
. the normal force
(horizonta
l
axis). Use either Logger
Pro
or graph paper.
4.Since Fmaximum static= μsN, the slope of this graph is the coefficient of static friction μs. Find the numeric value of the slope, including any units. Should a line fitted to these data pass through the origin?
5.In a similar graphical manner, find the coefficient of kinetic friction μk.Create a plot of the average kinetic friction forces vs.the normal force. Recall that Fkinetic= μkN. Should a line fitted to these data pass through the origin?
6.
Repeat steps 4 – 7 from Part II for the wooden block on its small area.
7.
Repeat steps 4 – 7 from Part III for the glass (block on its glass side).
8.Does the coefficient of kinetic friction depend on the area for the wooden block? Explain, using your experimental data.
9.Does the forceof kinetic friction depend on the weight of the block? Explain.
10.Does the coefficient of kinetic friction depend on the weight of the block?
11.Compare your coefficients of static friction and kinetic friction determined in Part I to that determined in Part II. Discuss the values. Do you expect them to be the same or different?
12. Compare your coefficients of static friction and kinetic friction determined in Part I to that determined in Part III. Discuss the values. Do you expect them to be the same or different?
13. Summarize of your data for the
μ
s
and
μ
k
for all parts in one final single table.
14. Write a good conclusion about this experience.

#### You've reached the end of your free preview.

Want to read all 5 pages?