As students watched a compressional pulse bounce back and forth on the horizontally suspended Slinky™, shown in Fig. 1, we wrote down the formula for the speed of the pulse and promised that later in the course we would derive the formula. The problem is we did not keep our promise in the course. Here is where we are keeping the promise. As part of our introduction to Einstein's special theory of relativity, we emphasized that the formula was for the pulse's speed relative to the Slinky medium. It would predict the pulse's speed past us only if we were at rest relative to that medium.
REFERENCES
1.
See E-PHTEAH-46-010803
http://ftp.aip.org/cgi-bin/epaps?ID=E-PHTEAH-46-010803
for accompany appendix and video. For more information on EPAPS, see http://www.aip.orgpubservs/epaps.html.
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David
Keeports
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See also
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Poothackanal
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,” Phys. Teach.
32
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(May 1994
). Their approach was to study resonant oscillations in springs in much the same way we studied resonant oscillations on the guitar string.4.
See also
Roset
Khosropour
, Rawlings
Lamberton
, and Scott
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, “SpacePhone: Propagating interest in waves
,” Phys. Teach.
31
, 529
–531
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Karl C.
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The shareware program MacScope II, which turns any USB computer into an audio oscilloscope, can be downloaded from: http:// www.physics2000.com.
7.
Elisha
Huggins
, “Speed of sound in metal pipes: An inexpensive lab
,” Phys. Teach.
46
, 13
–14
(Jan. 2008
).
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2008
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