Dr. Dave's answers to frequently-asked questions (FAQs), mostly from the AZB discussion forum
for more information,
see Sections 3.03 and 5.02 in The
Illustrated Principles of Pool and Billiards
and Disc I of the Video Encyclopedia of Pool Shots
ball speeds and travel distances
How do cue ball and object ball speeds and travel distances vary with cut angle?
For stun shots, see the graph and summary statements on page 2 of:
TP 3.2 - Ball speeds and distances after stun-shot impact
For roll shots, see the graph and summary statements on page 3 of:
TP A.16 - Final ball speeds, distances, and directions for natural roll shots
TP B.5 - Rolling CB, direct-hit hop and ball travel distances
Here are some useful conclusion statements from the analyses:
"Fundamentals - Part VII: speed control" (BD, March, 2009) also provides some good illustrations and examples.
What is tip height on the cue ball results in the best speed and distance consistency?
See optimal tip height for speed control.
cue ball path speed effects
What effect does shot speed have on the path the cue ball takes?
See cue ball path speed effects.
drills and advice
Where can I find general advice and drills for improving speed control?
See "Fundamentals - Part VII: speed control" (BD, March, 2009).
Target practice drills are also very helpful for developing CB speed and position control.
The following stun shot drill is also helpful for improving speed control: NV D.8 - Stun Shot Drill - from Vol-II of the Billiard University instructional DVD series.
What is the best way to hit a lag shot?
See lag shot.
optimal tip height for speed control
Where is the best height to hit the cue ball for speed and distance control and consistency?
To help achieve the best speed and distance consistency, it is best to hit the CB at about 20% of the radius above the center (0.2R), which is about 60% of the total ball height (see "d" in the illustration below). For illustrations and explanations, see "The Lag Shot" (BD, October, 2011) and "How High or Low Should You Hit the Cue Ball?" (BD, September, 2011). Hitting above center can also result in a more accuracy with CB direction (see follow accuracy).
rail cushion speed change
How much speed does the CB lose when it rebounds off a rail cushion?
For steep angles into a rail, where the CB path is close to perpendicular to the rail (i.e., almost straight into the rail), the CB loses about half of its speed after rebound and skid. For more information and demonstrations, see:
HSV B.15 - straight-on kick shot rebound losses and spin changes for roll, stun, and draw shots
At very shallow angles to the rail, where the CB is moving almost parallel to the rail, very little speed is lost off the rebound.
typical speeds for a range of shots
How fast does the CB travel for a range of shots?
Here are some typical values for various shot "speeds" in miles per hour (mph), feet per second (fps), inches per second (ips), centimeters per second (cm/s) and meters per second (m/s):
soft touch: <1 mph = <1.5 fps = < 18 ips = < 45 cm/s
slow: 1-2 mph = 1.5-2.9 fps = 18-35 ips = 45-89 cm/s
medium: 2-4 mph = 2.9-5.9 fps = 0.89-1.9 m/s
fast: 4-7 mph = 5.9-10.3 fps = 1.9-3.2 m/s
power shot: 7-10 mph = 10.3-14.7 fps = 3.2-4.5 m/s
powerful break: 25-30 mph = 37-44 fps = 11-13 m/s
ridiculously powerful break: 35 mph = 51 fps = 16 m/s
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