Question 2
FRICTION FORCE
Friction force between two contacting surfaces plays important role in our daily life. The surfaces
of vehicle tires and the surface of roads must not be smooth to generate appreciable friction
forces between them. This friction force avoids a slippery motion of the vehicles, which may
cause the occurrence of unexpected accidents. On the other hand, lubricant oils are used to
reduce the friction forces between the moving parts in machines to avoid the occurrence of any
damage on the machine as well as to enhance the efficiency of energy usage. The friction force
between two surfaces depends on the contacting forces between these surfaces (how strong one
surface pulls another surface) and the nature of the contacting surfaces. Mathematically, the
friction force between two contacting surfaces just before a relative motion between two surfaces
occurs can be expressed as
Fs = C N
where
Fs : the friction force
N : the contacting force between two surface
C : a factor which describes the nature of the contacting surfaces. This factor is known as
the coefficient of friction.
Objectives:
In this experiment, you will measure the friction force between two contacting bodies using two
methods: i.e., (a) using a spring balance and without spring balance (b). You must compare the
results obtained by these two methods.
Materials:
1\. Wood plate
2\. Three blocks (200 g, 300 g, and 400 g) having different surface roughness:
(a) covered with a coarse sand paper,
(b) covered with a fine sand paper,
(c) covered with a mica
3\. Spring balance
4\. Ruler
Questions:
Determine the coefficient of frictions between each block and plane surface using a spring
balance. You must report the method (procedure) of measurement.
A.1. Surface covered with coarse sand paper
| Block mass (kg) | Contacting force or weight (N) | Friction force just before surface slippery (N) | Coefficient of friction |
| --- | --- | --- | --- |
| 0.2 | | | |
| 0.3 | | | |
| 0.4 | | | |
A.2. Surface covered with fine sand paper
| Block mass (kg) | Contacting force or weight (N) | Friction force just before surface slippery (N) | Coefficient of friction |
| --- | --- | --- | --- |
| | | | |
| | | | |
| | | | |
A.2. Surface covered with mica
| Block mass (kg) | Contacting force or weight (N) | Friction force just before surface slippery (N) | Coefficient of friction |
| --- | --- | --- | --- |
| | | | |
| | | | |
| | | | |
The source repeats label A.2. Blank entries remain blank.
Friction force between two contacting surfaces plays important role in our daily life. The surfaces
of vehicle tires and the surface of roads must not be smooth to generate appreciable friction
forces between them. This friction force avoids a slippery motion of the vehicles, which may
cause the occurrence of unexpected accidents. On the other hand, lubricant oils are used to
reduce the friction forces between the moving parts in machines to avoid the occurrence of any
damage on the machine as well as to enhance the efficiency of energy usage. The friction force
between two surfaces depends on the contacting forces between these surfaces (how strong one
surface pulls another surface) and the nature of the contacting surfaces. Mathematically, the
friction force between two contacting surfaces just before a relative motion between two surfaces
occurs can be expressed as
Fs = C N
where
Fs : the friction force
N : the contacting force between two surface
C : a factor which describes the nature of the contacting surfaces. This factor is known as
the coefficient of friction.
Objectives:
In this experiment, you will measure the friction force between two contacting bodies using two
methods: i.e., (a) using a spring balance and without spring balance (b). You must compare the
results obtained by these two methods.
Materials:
1\. Wood plate
2\. Three blocks (200 g, 300 g, and 400 g) having different surface roughness:
(a) covered with a coarse sand paper,
(b) covered with a fine sand paper,
(c) covered with a mica
3\. Spring balance
4\. Ruler
Questions:
Determine the coefficient of frictions between each block and plane surface using a spring
balance. You must report the method (procedure) of measurement.
A.1. Surface covered with coarse sand paper
| Block mass (kg) | Contacting force or weight (N) | Friction force just before surface slippery (N) | Coefficient of friction |
| --- | --- | --- | --- |
| 0.2 | | | |
| 0.3 | | | |
| 0.4 | | | |
A.2. Surface covered with fine sand paper
| Block mass (kg) | Contacting force or weight (N) | Friction force just before surface slippery (N) | Coefficient of friction |
| --- | --- | --- | --- |
| | | | |
| | | | |
| | | | |
A.2. Surface covered with mica
| Block mass (kg) | Contacting force or weight (N) | Friction force just before surface slippery (N) | Coefficient of friction |
| --- | --- | --- | --- |
| | | | |
| | | | |
| | | | |
The source repeats label A.2. Blank entries remain blank.