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Physics
2000
Relativistic metersticks
Tom Greenslade
Kenyon College, [email protected]
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Recommended Citation
“Relativistic Metersticks”, The Physics Teacher, 38, 315 (2000)
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Relativistic metersticks
Thomas B. Greenslade Jr.
Citation: The Physics Teacher 38, 315 (2000); doi: 10.1119/1.880548
View online: http://dx.doi.org/10.1119/1.880548
View Table of Contents: http://scitation.aip.org/content/aapt/journal/tpt/38/5?ver=pdfcov
Published by the American Association of Physics Teachers
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Relativistic Metersticks
Thomas B. Greenslade, Jr., Department of Physics, Kenyon College, Gambier, OH 43022;
[email protected]
I
n a Physical Science Study
Committee summer course taught
by Richard Weidner and Robert Sells
in 1960, Duke Sells displayed a relativistic meterstick. He was an active
man, fleet of foot and a good touch
football player, and his undergraduate
students had made the meterstick for
him to recognize his speed. It was
perhaps 0.6 m long, suggesting that
he was speeding past us at 80% of c,
the speed of light.
Recently I made the set of relativistic metersticks shown in Fig. 1.
These represent the apparent length
of a meterstick passing the stationary
observer with a speed v, and are
marked with the v/c ratio. The
unmarked stick is actually one meter
long, and represents the meterstick in
the reference frame of the observer.
The lengths were calculated using the
length contraction equation: L =
L0[1 – (v/c)2]½. Table I shows the
lengths of the meterstick as a function
Table I. Length of a meterstick passing lengthwise past a stationary observer at relative
speed v/c.
v/c
L in meters
0.995
0.0999
0.99
0.141
0.98
0.199
0.95
0.312
0.92
0.392
0.90
0.436
0.80
0.600
0.60
0.800
0.30
0.954
Relativistic Metersticks
Fig. 1. Upper stick is 1.000 m long. Lower sticks represent the meterstick as it would appear to a
stationary observer as it moved by with various speeds. Number on the stick represents v/c.
THE PHYSICS TEACHER
Vol. 38, May 2000
315
This article is copyrighted as indicated in the article. Reuse of AAPT content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
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