3B Scientific Friction Measuring Apparatus User Manual

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 x105 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