3B SCIENTIFIC PHYSICS U52006 Manual De Instrucciones página 5

aligned to the horizontal. The disc can be made to rotate
either manually or by means of a string. The double ball-
race bearing guarantees almost frictionless rotation that
goes on for an extended period of time. The open con-
struction of the gyroscope facilitates excellent observa-
tion of the gyroscopic phenomena.
Scale:
Scale divisions:
Disc:
Mass of disc:
Mass of counterweights:
Total mass:
2.2 Accessories for the gyroscope
The set of accessories for the gyroscope U52006 consists
of an additional disc and a counterweight. It is used to
demonstrate the cancellation of gyroscopic forces when
two discs rotate in opposite directions with the same
rotational speed.
3. Theory
A gyroscope is a rigid body that rotates around an axis
that is fixed at one point. If no external turning moment
is applied, the axis of the gyroscope (being equivalent to
the axis of its angular momentum) maintains its position
in space. If, however, an external force is applied to the
axis, then this turning moment effects a change in angu-
lar momentum. As a result, the axis is laterally displaced.
The gyroscope moves in a direction perpendicular to both
its own axis and to the acting force. This motion is called
precession. If an impulse is applied to the axis of the
gyroscope when it is spinning normally, the resulting turn-
ing moment causes an additional angular motion and
the gyroscope starts to wobble. This wobbling motion is
called nutation. In general, both motions are superim-
posed on one another.
4. Operation
• Place the tripod stand
work surface.
• Insert and fix the stand rod
• Insert the gyroscope axle
• Align the device in a horizontal position by using the
spirit level .
bm
• Slide the disc
and the counterweights
1
along the axle. Use the locking ring to securely fix the
disc and balance the gyroscope. Use the adjusting
screw for making fine adjustments.
9
• Rotate the gyroscope manually or with the help of a
string wound into the bobbin
5. Examples of experiment
In order to conduct the experiments, the following addi-
tional equipment is required:
• Mechanical adding stopwatch U11901 for measuring
the precession and nutation frequencies.
– 45° to +45°
1°
250 mm Ø
1500 g
50 g, 1400 g
4650 g
on a level, non-vibrating
5
into the tripod stand.
6
into its bearing.
2
,
7 8
.
3
• Stand rod U15002 and bosshead U13250 for fixing the
gyroscope.
• Light barrier U18020 and digital counter U21005 for
measuring the period of rotation of the gyroscope
disc.
5.1 Determining the moment of inertia I of the disc
• Set up the gyroscope as shown in Fig. 1 and balance
it.
• A known turning moment D is applied to the disc.
The resulting angular momentum dω/dt is measured.
The following equation applies:
• To apply this turning moment, wind a string around
the bobbin, suspend a weight from one end of the
string and allow the weight to fall.
• Turning moment D = mgr (m = mass of accelerating
weight and r = radius of bobbin).
• To determine the angular acceleration, measure the
time ∆t between releasing the disc and when the
weight hits the floor.
• Next determine the angular velocity ω
the light barrier to measure the period of one disc
revolution. Before starting the experiment, glue a thin
strip of paper onto the rim of the disc.
• The moment of inertia I is calculated using the equa-
tion:
ω
d
=
dt
Fig. 1: Determining the moment of inertia of the disc
5.2 Precession
• The aim of the experiment is to demonstrate preces-
sion and to study the interdependence of the period
of precession and the frequency of rotation of the
disc.
• Set up the gyroscope as shown in Fig. 2 and balance
it.
5
ω
d D
=
dt I
. To do so, use
E
∆
ω
D t
E I =
ω
∆
t
E