Download Shoe Lab

Name:________________________
Per:______ Date: _______________
Shoe Lab
Today you will be investigating the force of friction. There are two types of friction
Static Friction:
Kinetic Friction:
Preliminary questions:
1) What do you think causes friction?
2) What types of materials have low friction?
3) What types of materials have high friction?
You will be looking at two different situations.
First, you will pull on the scale as much as possible without moving the shoe.
4)
Draw a free body diagram labeling all of the forces on the shoe (gravity, support, pull,
static friction)
Is there a net force on the shoe? How do you know?
Name:________________________
Per:______ Date: _______________
Next, you will pull the shoe along the ground at a constant velocity.
5) Draw a free body diagram labeling all of the forces on the shoe (gravity, support, pull,
kinetic friction)
Is there a net force on the shoe? How do you know?
Experimental Design
You will be testing your shoe on three different surfaces. Then you will be comparing you
results with results of your other group members.
Type of Shoe:___________________________________ Weight of Shoe:________________
Surface Tested
Static Friction
Kinetic Friction
Type of Shoe:___________________________________ Weight of Shoe:________________
Surface Tested
Static Friction
Kinetic Friction
Name:________________________
Per:______ Date: _______________
Type of Shoe:___________________________________ Weight of Shoe:________________
Surface Tested
Static Friction
Kinetic Friction
Analysis
1) Which type of friction was highest, static or kinetic?
2) Which shoe had the highest friction value?
3) For the shoe you listed in #2, which surface had the highest friction value?
4) What factors affected the frictional forces?
Name:________________________
Per:______ Date: _______________
Finding the coefficient of friction
The coefficient of friction is a number which describes how strong friction is between two
surfaces. It is represented by the symbol .
f is the force of friction
W is the weight of the object
is a ratio that means we are comparing two values. In this case we are
comparing two forces
IS A NAKED NUMBER! It has no units.
1. Using the shoe with the highest friction value, calculate  for both static and kinetic
friction.
2. +The values for range from 0-1. The higher the number, the stronger the force of
friction. Based on your data does your answer make sense? Explain why or why not.