We revisit a recent analysis of the time of fall of a magnet as it slows down while passing through a conducting tube. We complement recent work by considering the effect of the thickness of the tube on the time of fall. The resulting expression gives a more accurate expression for the time of fall.
REFERENCES
1.
C. S.
MacLatchy
, P.
Backman
, and L.
Bogan
, “A quantitative magnetic braking experiment
,” Am. J. Phys.
61
, 1096
–1101
(1993
).2.
J. A.
Pelesko
, M.
Cesky
, and S.
Huertas
, “Lenz’s law and dimensional analysis
,” Am. J. Phys.
73
, 37
–39
(2005
).3.
K. D.
Hahn
, E. M.
Johnson
, A.
Brokken
, and S.
Baldwin
, “Eddy current damping of a magnet moving through a pipe
,” Am. J. Phys.
66
, 1066
–1076
(1998
).4.
W. M.
Saslow
, “Maxwell’s theory of eddy currents in thin conducting sheets, and applications to electromagnetic shielding and MAGLEV
,” Am. J. Phys.
60
, 693
–711
(1992
).5.
H. D.
Wiederick
, N.
Gauthier
, D. A.
Campbell
, and P.
Rochon
, “Magnetic braking: Simple theory and experiment
,” Am. J. Phys.
55
, 500
–503
(1987
).6.
M.
Marcuso
, R.
Grass
, D.
Jones
, and C.
Rowlett
, “Magnetic drag in the quasi-static limit: Experimental data and analysis
,” Am. J. Phys.
59
, 1123
–1129
(1991
).7.
E.
Buckingham
, “On physically similar systems: Illustrations of the use of dimensional equations
,” Phys. Rev.
4
, 345
–376
(1914
).© 2007 American Association of Physics Teachers.
2007
American Association of Physics Teachers
AAPT members receive access to the American Journal of Physics and The Physics Teacher as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.
