3B SCIENTIFIC PHYSICS 1002956 Istruzioni per l'uso - Pagina 5
Sfoglia online o scarica il pdf Istruzioni per l'uso per Prodotti per l'educazione scientifica 3B SCIENTIFIC PHYSICS 1002956. 3B SCIENTIFIC PHYSICS 1002956 5. Torsion pendulum according to prof. pohl
Stampa la pagina• After measuring the period T the natural frequency
of the system ω
can be obtained from
0
ω
= 2 π/T = 3.3069 Hz
0
• The most extreme deflection arises at a motor volt-
age of 7.6 V, i.e. the resonance case occurs.
• Then the same experiment is performed with an
eddy current brake connected at currents of
Ι = 0.2 A, 0.4 A and 0.6 A.
Ι Ι Ι Ι Ι = 0.2 A
Motor voltage V
3.0
4.0
5.0
6.0
7.0
7.6
8.0
9.0
10.0
Ι Ι Ι Ι Ι = 0.4 A
Motor voltage V
3.0
4.0
A
[skt]
20
15
10
5
1
0
Resonance curves
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ϕ
0.9
1.1
1.2
1.7
2.9
15.2
4.3
1.8
1.1
ϕ
0.9
1.1
3
5
1
2
4
5.0
6.0
7.0
7.6
8.0
9.0
10.0
Ι Ι Ι Ι Ι = 0.6 A
Motor voltage V
3.0
4.0
5.0
6.0
7.0
7.6.0
8.0
9.0
10.0
• From these measurements the resonance curves can
be plotted in a graph depicting the amplitudes
against the motor voltage.
• The resonant frequency can be determined by find-
ing the half-width value from the graph.
I=0,0A
I=0,2A
I=0,4A
I=0,6A
6
7
8
9
10
10
1.3
1.8
3.6
7.4
3.6
1.6
1.0
ϕ
0.9
1.1
1.2
1.6
2.8
3.6
2.6
1.3
1.0
u[v]