Friction
Experiment Question:
-
What type of force is friction, forward or backward?
-
What are the two variables that affect the strength of friction?
|
Definition:
- Friction - When two objects rub or slide against each other and creates a force
Hypothesis:
It is a backward force.
-
How fast the objects rub against each other
-
The roughness of the surfaces
Experiment 1: What type of force is friction?
Results:
1. What happened to the speed of the block as it slid across the floor?
The object slowed to a stop proving that it is a backward force.
2. So, what type of force is friction?
Backward
Experiment 2:
- Take the block with the ring on it and place the block on the table.
-
Take the spring scale and hook it onto the ring. Hook it from underneath the Ring
-
Pull slowly and straight out until the block moves. You are looking to see how much force it takes to move the block. Record the number from the spring scale in the data table.
-
Repeat 4 more times.
-
Repeat steps 1 – 4 for one wooden block on sand paper. Make sure to hold the sand paper down so the sand paper does not move when using the spring scale.
- Stack all 3 wooden blocks on top of each other. The Wood with the ring on it should be on the bottom.
-
Repeat steps 1 – 4 for 3 wooden blocks on table.
Data Table/Results:
|
Amount of Force to move the blocks (N)
|
|
Experiment
|
One Wooden block on table
|
One Wooden Block on sand paper
|
3 Wooden blocks
on table
|
|
Trial 1
|
0.4
|
1.4
|
1.2
|
|
Trial 2
|
0.6
|
1.8
|
1.2
|
|
Trial 3
|
0.4
|
1.6
|
1.4
|
|
Trial 4
|
0.5
|
1.6
|
1.3
|
|
Trial 5
|
0.4
|
1.7
|
1.3
|
|
Average
|
0.46
|
1.62
|
1.28
|
|
Uncertainty
|
0.1
|
0.2
|
0.1
|
Data Analysis/Discussion:
-
What two variables did you change that affected the strength of friction?
- The weight
- The roughness of the surface
-
How does increasing weight affect the strength of friction? Give evidence (numbers) from the data table.
More weight made the object have to overcome static friction. With one block, only 0.46 N were needed to move the block but with three blocks, that number was almost tripled, 1.28. So evidently, weight is a huge factor in the amount of friction.
-
How does the type of surface affect the strength of friction? Give evidence (numbers) from the data table
Sandpaper's rough texture added even more friction to the single block than the three blocks. The roughness of a surface seems to play a larger role in producing friction. On the sand paper, the block produced over three times the amount of friction than it did on the table, 1.62.
4. Draw force arrow diagrams. (We will do this together in class)
| One wooden block on table |
|
|
| One wooden block on sand paper |
|
|
| Three wooden blocks on table |
|
|
|
Summary
|
|
Friction is a backwards force. Two variables that affect the strength of friction are the weight of the objects rubbing against eachtother, and the roughness of each object.
|
Comments (0)
You don't have permission to comment on this page.