Understanding degrees of freedom in classical mechanics is fundamental to characterizing physical systems. Counting them is usually easy, especially if we can assign them a clear meaning. However, the precise definition of a degree of freedom is not usually presented in first-year physics courses since it requires mathematical knowledge only learned in more advanced courses. In this paper, we use a pedagogical approach motivated by simple but non-trivial mechanical examples to define degrees of freedom and configuration spaces. We highlight the role that topology plays in understanding these ideas.
REFERENCES
1.
Wikipedia Contributors
, see https://en.wikipedia.org/wiki/Degrees_of_freedom_(mechanics) for “
Degrees of Freedom (Mechanics)—Wikipedia, The Free Encyclopedia
” (2023
).2.
E. W.
Weisstein
, see https://mathworld.wolfram.com/DegreeofFreedom.html for “
Degree of Freedom—MathWorld, A Wolfram Web Resource
” (2023
).3.
4.
R. P.
Feynman
,
R. B.
Leighton
, and
M.
Sands
, The Feynman Lectures on Physics: New Millennium Edition
(
Basic Books
,
New York, NY
, 2010
).5.
A.
Sommerfeld
, Mechanics: Lectures on Theoretical Physics
(
Academic Press
,
New York
, 2016
), Vol.
1
.6.
L.
Landau
and
E.
Lifshitz
, Mechanics: Volume 1 (Course of Theoretical Physics)
(
Elsevier Science
, Oxford, UK, 1976
).7.
8.
V.
Arnold
, Mathematical Methods of Classical Mechanics
, 2nd ed. (
Springer
,
New York
, 1989
).9.
J. Fernando
Barbero G
,
Jorge
Prieto
, and
Eduardo J. S.
Villaseñor
, “
Gauge invariance in simple mechanical systems
,” Eur. J. Phys.
36
(5
), 055005
(2015
).10.
J. Fernando
Barbero G
,
Benito A.
Juárez-Aubry
,
Juan
Margalef-Bentabol
, and
Eduardo J. S.
Villaseñor
, “
Quantization of scalar fields coupled to point masses
,” Class. Quantum Grav.
32
(24
), 245009
(2015
).11.
12.
13.
See supplementary material online for a non-orientable example.
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2024
Author(s)
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