We develop a model for the velocity of a projectile in a vacuum cannon. The theoretical maximum velocity is independent of the vacuum cannon diameter and projectile mass and is significantly lower than the speed of sound. Experimental measurements support the theory as an upper limit.
Topics
Speed of sound
REFERENCES
1.
Physics Instructional Resource Association (PIRA) Demonstration Classification Scheme 2B30.70.
2.
J.
Cockman
, “Improved Vacuum Bazooka
,” Phys. Teach.
41
, 246
–247
(2003
).3.
N. A. Downie, Vacuum Bazookas, Electric Rainbow Jelly, and 27 Other Saturday Science Projects (Princeton U. P., New York, 2001).
4.
This definition was chosen purely to simplify the analysis. Interestingly enough, it also is the length of an air column with a mass equal to the mass of the projectile.
5.
R. Feynman, R. B. Leighton, and M. L. Sands, The Feynman Lectures on Physics (Addison–Wesley, Reading, MA, 1989), Vol. 1.
6.
PASCO Scientific, 〈http://www.pasco.com〉, part #ME-9498A.
7.
The ballistics of many guns can be found at 〈http://www.volny.cz/buchtik/Revo/Ballistic_Info_komplet.htm〉.
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© 2004 American Association of Physics Teachers.
2004
American Association of Physics Teachers
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