Friction Measuring Apparatus
3B SCIENTIFIC
Friction Measuring Apparatus 1009942
Instruction sheet
07/12 DML/ALF
®
PHYSICS
1 Friction surface
2 Clamp for dynamometer
3 Dynamometer
4 Stopper for the friction bod-
ies
5 Friction bodies
6 Additional weights
7 Sliders
8 Protractor
1. Description
The friction measuring apparatus is used to
measure static and rolling friction between different kinds of surfaces.
A friction track in the form of a mounted, rotating
U-shaped structure made of aluminium serves as
the basis for the experiments. Between the friction bodies and the friction plane, there is a long,
inlaid friction surface made of plastic, which can
be pulled at a uniform velocity. At the opposite
end, a dynamometer is horizontally clamped to
the friction track. The dynamometer shows the
frictional forces between the surfaces, resulting
from the movement of the sliding friction surface.
When the friction surface begins to move, the
body resting upon it experiences static friction
and is dragged along with the sliding surface. As
the sliding friction surface continues to be moved
at uniform velocity, the static friction changes to
sliding friction and the friction body remains at a
state of rest relative to the friction plane.
The friction bodies have surfaces of different
areas and degrees of roughness. This makes it
possible to investigate the influence the area of
contact and the nature of the surface has on the
frictional forces.
It is possible to vary the angle of the friction
track, thereby creating an incline to the horizontal plane. In this way, the normal force with
which the friction body acts upon the particular
surface can be made to vary.
2. Scope of delivery
1 Friction plane
1 Friction body A
1 Friction body B
1 Friction body C
1 Sliding friction surface
1 Dynamometer
1 Stopper for the friction bodies
1 Sliders, rubber-coated
1 Sliders, Teflon-coated
1 Sliders, uncoated
3 Additional weights, 100 g
1
3. Technical data
4. Set-up
Friction track
U-shaped track: 600 x 80 x 20 mm
Protractor: 0° – 60°
3
Sliding friction surface
Material: PVC, smooth on one
side and coarse on the
other side
Length: 850 mm
Friction body A
Dimensions: 79 x 38 x 73 mm
3
Material: PVC
Surface: Uncoated
Surface area ratio: 2:1
Weight: 325 g approx.
Fastening rings: 2
Friction body B
Dimensions: 73 x 20 x 47 mm
3
Material: PVC
Surface: Coated with velour pa-
per
Weight: 100 g approx.
Additional weights
Design: To fit friction body B
Weight: 100 g
Sliders
Design: To fit friction body B
Material: Aluminium
Surface: Rubber-coated (No. 1),
Teflon-coated (No. 2),
Uncoated (No. 3)
Dimensions: 55 x 55 x 15 mm
3
Friction body C
Dimensions: 75 x 31 x105 mm
3
Surface: Coated with velour pa-
per
Weight: 325 g
Securing rings: 2
Castors: 2, ball-bearings
Dynamometer
Measuring range: 2 N, tension and com-
pression
• Secure the dynamometer by means of the
clamp.
• Attach a stopper for the friction body to the
U-shaped track (the stopper prevents any
sudden recoil of the friction body that might
arise as the sliding friction surface is pushed
back.)
5. Measurements conducted on a horizontal
friction plane
• Align the friction track so that the pointer on
the protractor is in the zero position.
• Insert the sliding friction surface into the
friction track either with its smooth or coarse
facing down. Then place a friction body onto
the sliding friction surface. (See Fig. 1 and
Fig. 2.)
5.1 Static friction
• Pull the sliding friction surface, making sure
it is displaced with a uniform motion.
• Read the maximum value from the dyna-
mometer while the friction body is still being
dragged along with the sliding friction surface.
• Perform this measurement on several occa-
sions and calculate the average.
This value represents a measure of the static
frictional force.
5.2 Sliding friction
• Conduct measurements as described under
5.1. However, take the reading on the dynamometer as soon as the friction body has
stopped moving along with the sliding friction surface.
• Perform this measurement on several occa-
sions and calculate the average.
This value represents a measure of the sliding
frictional force.
Fig. 1: Investigation of static and sliding friction with
friction body A with two different contact areas.
2
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