Sports Sensors gloveRADAR GR360 Owner's Manual page 6

7. Place the two free cord ends within the band loop, sliding the band to the
proper place to encircle the cord bundle. Long loose ends can be tucked
between the Glove Radar ® and the glove. The Glove Radar
for use.
8. The lower cord attachment can also be made by wrapping the lace
around the wrist strap of a small glove.
9. If the glove does not have fingers, such as a catcher's mitt or first
baseman's glove, use the top edge lacing for the top two cord attach
ments. Slip the cord tip under the lacing and wrap the cord around
the lace for a secure attachment.
10. The Glove Radar can also be attached behind the thumb of a
®
catcher's mitt.
TIP—Be sure to keep the Glove Radar
becomes loose, untie the knot, pull out the cord slack, and re-tie the knot.
® is now ready
attached snugly to the glove. If it
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TIP—The top of the Glove Radar
7.5 cm below the glove fingertips. If the ends of the cord are too long, take
up the extra length by attaching to a lower glove feature, or locating the
Glove Radar lower from the glove finger tips. Move it closer to the tips if
®
more cord length is needed.
VARIABLES OF BALL SPEED RADAR MEASUREMENTS
Ball Speed Slow-Down
When a ball leaves the thrower's hand, it is travelling at its' maximum
velocity. Air resistance (drag) causes the ball to decrease in velocity as it
travels away from the thrower. The rate at which the ball slows-down is
dependent upon many factors. Robert K. Adair, Sterling Professor of Physics,
Yale University, describes in great detail the flight of a thrown (and batted)
baseball in his outstanding book, "The Physics of Baseball"*. Written for the
layperson, but appropriately supported by theory, the book summarizes the
Professor's conclusion (page 33) that a typical (Major League) fastball
slows-down at a rate of about 1 mile-per-hour for every 7 feet of travel.
Thus, a ball thrown by a pitcher will reach home plate, 60 feet 6 inches
away, at a speed about 9 miles-per-hour slower than when it left the
pitcher's hand. Many variables which affect the air resistance "drag" on the
ball, and associated air turbulence, enter into this
conclusion, including air density, temperature, altitude, barometric pressure,
wind velocity and direction, etc.; as well as the ball cross- section area,
surface roughness, stitch height and stitch orientation relative to ball spin
axis; and ball velocity. However, for the purposes of this discussion, and the
applicability to using ball speed measuring devices, it is sufficient to apply
the Professor's generalization that a ball slows-down at a rate of 1 MPH for
each 7 feet of travel from the thrower's hand. When asked the specific
question about the deceleration of a softball, Professor Adair offered the
opinion, interpreted by this writer, that the increased drag, relative to
a baseball, would be offset by the momentum of the heavier softball,
resulting in approximately the same rate of slow-down as the baseball.
Radar Speed Variables
Several different "Radar Speed Guns" are used to measure the speed of a
thrown ball. Some radars, referred to as "fast guns", measure the speed of
the ball within a few meters after it leaves the hand of the thrower or pitcher.
Since the speed at "release" is the pitcher's maximum, it is often the
speed that most players use as a reference, since everyone is generally
interested in quoting their "fastest" speed. Although these "fast guns" are
excellent instruments, they can occasionally present an erroneous speed
indication due to the pitcher's motion, leg kick, arm swing, or other false
target anomalies often referred to as "ghost" readings for all radars.
should be positioned within about 2.5 to
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