BASEBALL & SOFTBALL MOVIES
PITCHING
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How to pitch a
ball with a sideways break of six feet or more. Step 1: Polish
one side of ball Step 2.
Roughen other side or glue a loop of string around that side Step 3: Reduce
ball mass to about 15 or 20 gram. Step 4: Hold
ball with smooth side on your right. Step 5: Throw
a fastball straight at camera (with backspin).
My pitching
effort is of no practical value (like a lot of physics) but at least it demonstrates the physics behind the swing of a
cricket ball with its rough and smooth
sides and seam. How about a baseball? Does it have a rough and a smooth
side or doesn't it? What if it is spinning? That might be of practical
interest, at least for knuckleballs.
Here is a 100
mm diameter polystyrene ball with a baseball seam glued to the
ball. It breaks 90 cm over a distance of 5 m if the seam is aligned
properly, otherwise there is no break or a smaller break. 90 cm break
70 cm break
no break (all 300
fps)
BATTING
The center of
percussion (COP) of a hand held bat is not the same as the COP of
a freely suspended bat. This movie shows that the axis of rotation of
a hand held bat is near the wrists (regardless of the impact point on the bat).
The COP is NOT the sweet spot of a bat.
Low speed
baseball bounce, filmed at 1000 frames/s
Why are
baseballs and softballs so hard? Softer balls would reduce injuries, help prevent
bats breaking and reduce the trampoline effect. The Kenko ball here (a hollow, rubber ball) is 10 times softer
than an adult baseball and 3 times stiffer than a
tennis ball. It is used in youth leagues in
Japan, Australia etc.
Click for more info
How fast can
you spin a 12 inch softball? 1000 rpm? (12 in is the circumference!)
Swing speed vs
bat weight. Light bats can be swung faster. By how much?
232 g bat 871 g bat 1333
g bat
Measuring
outgoing ball speed at different
impact points on a bat
Impact
at 2 cm
Impact at 7 cm Impact at 12 cm
Impact
at 17 cm Impact at 24 cm Impact at 31 cm
Strike at 2cm Strike
at 7 cm Strike
at 12 cm
Strike at 17 cm Strike at 24 cm Strike at 31 cm