A billiard ball struck by a cue travels in the same direction as the cue unless the ball is struck toward one side in order to impart sidespin. In that case the ball deflects or “squirts” away from the line of approach of the cue, typically by a few degrees. Measurements and calculations are presented showing how a cue tip slides across the ball if it is unchalked, resulting in a large squirt angle, and how it grips the ball when it is chalked, resulting in a smaller squirt angle.
REFERENCES
1.
D. G.
Alciatore
, The Illustrated Principles of Pool and Billiards
(Sterling
, New York
, 2004
). The relevant physics is described at ⟨billiards.colostate.edu⟩.2.
3.
R. E.
Wallace
and M. C.
Schroeder
, “Analysis of billiard ball collisions in two dimensions
,” Am. J. Phys.
56
, 815
–819
(1988
),R. E.
Wallace
and M. C.
Schroeder
, Am. J. Phys.
57
, 476
–478
(1989
).4.
See, for example, ⟨billiards.colostate.edu⟩ and ⟨www.sfbilliards.com/articles/BD-articles.html⟩.
5.
R.
Shepard
, “Everything you always wanted to know about squirt, but were afraid to ask
,” ⟨www.sfbilliards.com/Shepard-squirt.pdf⟩ or ⟨billiards.colostate.edu⟩.6.
Lenox Softworks, ⟨www.lsw.com/videopoint⟩.
7.
8.
R.
Cross
, “Measurements of the horizontal coefficient of restitution for a superball and a tennis ball
,” Am. J. Phys.
70
, 482
–489
(2002
).9.
R.
Cross
, “Grip-slip behavior of a bouncing ball
,” Am. J. Phys.
70
, 1093
–1102
(2002
).10.
R.
Cross
and A.
Nathan
, “Experimental study of the gear effect in ball collisions
,” Am. J. Phys.
75
, 658
–664
(2007
).© 2008 American Association of Physics Teachers.
2008
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.
