PASCO ME-6694 TORSION PENDULUM - Manual (Page 19)

012–06339A Torsion Pendulum
15
Figure TN1.3
Typical data for determining the period of rotation (T) for the three wire diameters (disk plus cylinder)
I
disk plus cylinder
(using mass and radius measurements) 6.7 x 10 -4 kg/m 2
**from Part B
mass of cylinder 0.468 kg*
R
1
of cylinder 0.027 m*
R
2
of cylinder 0.039 m*
*may vary somewhat
Part C
Table TN1.3
Calculation of I
disk plus cylinder
from torsional spring constants
( κ ) of wires
Run wire diameter κ * T I
(inches) (N·m) (s) (kg/m 2 )
1 0.032 0.008 1.826 6.8 x 10 -4
2 0.047 0.036 0.861 6.8 x 10 -4
3 0.062 0.113 0.500 7.2 x 10 -4
*from part A
I = 1.4 x 10 -4 kg/m 2 (disk)** + 5.3 x 10 -4 kg/m 2 (cylinder)
I = 6.7 x 10 -4 kg/m 2
Time (s)
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
-5
.0
-4
.0
-3
.0
-2
.0
-1
.0
0
1.
0
R
un
#4
, 5, 6
A
n
gu
lar
P
o
s
iti
on
(
ra
d)
0.032 in. wire
0.047 in. wire 0.062 in. wire