The spear thrower (atlatl) is a hunting weapon with very ancient origins. It is a lever that enables wrist rotation to make a substantial increase in the velocity of a thrown spear. A model for throwing a projectile with an atlatl is presented. This model is used to analyze the projectile velocity as a function of the dimensions, rigidity, and mass distribution of the atlatl and mass of the projectile. The model assumes that the throwing force and wrist torque are functions only of the horizontal position of the throwing hand and that the spear is sufficiently long that the atlatl applies only a horizontal force to the proximal end of the spear. The applied force and torque were derived from a high-speed video digitizer plus the known physical dimensions of the atlatl and spear.

1.
The World Atlatl Association, 〈http//www.worldatlatl.org/〉.
2.
A Web site that advertises the Chuckit, a device for throwing tennis balls, is 〈http://www.caninehardware.com/products_chuckits.html〉.
3.
C.
Howard
, “
The Atlatl: Function and performance
,”
Am. Antiq.
39
,
102
–
104
(
1974
).
Google Scholar
Crossref
Search ADS
 
4.
M. W.
Hill
, “
The atlatl or throwing stick. A recent study of atlatls in use with darts of various sizes
,”
Tenn. Archaeol. Soc.
IV
(
4
),
37
–
44
(
1948
).
Google Scholar
 
5.
Anan
Raymond
, “
Experiments in the function and performance of the weighted atlatl
,”
World Archaeol.
18
(
2
),
153
–
177
(
1986
).
Google Scholar
Crossref
Search ADS
 
6.
P. E.
Klopsteg
, “
Physics of bows and arrows
,”
Am. J. Phys.
11
,
175
–
180
(
1943
).
Google Scholar
Crossref
Search ADS
 
7.
Brian Cotterell and Johan Kamminga, Mechanics of Pre-industrial Technology (Cambridge U. P., Cambridge, 1992), Chap. 7.
8.
J. L.
Palter
, “
Design and construction of Australian spear thrower projectiles and hand thrown spears
,”
Archaeol. Phys. Anthropol. Oceania
12
,
161
–
172
(
1977
).
Google Scholar
 
9.
George C. Stone, A Glossary of the Construction, Decoration and Use of Arms and Armor in all Countries and in all Times (Jack Brussel, New York, 1934).
10.
T. R. Hester, M. P. Mildner, and L. Spencer, Great Basin Atlatl Studies (Ballena, Ramona, CA, 1974), a master’s thesis in archaeology on the atlatls and projectiles used in this region.
11.
〈http://www.atlatl.com/〉 the Web site for BPS Engineering, the company that made the atlatl and dart used in the experiment.
12.
T. J.
Bensky
, “
Computer sound card assisted measurements of the acoustic Doppler effect for accelerated and unaccelerated sound sources
,”
Am. J. Phys.
69
,
1231
–
1236
(
2001
).
Google Scholar
Crossref
Search ADS
 
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© 2003 American Association of Physics Teachers.
2003
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