1.
2. "1.09 The ball shall be a sphere formed by yarn wound around a small core of cork,
rubber or similar material, covered with two strips of white horsehide or cowhide, tightly
stitched together. It shall weigh not less than five nor more than 5 1/4 ounces avoirdupois
and measure not less than nine nor more than 9 1/4 inches in circumference." http://mlb.mlb.com/mlb/downloads/y2012/Official_Baseball_Rules.pdf
3. Once upon a time, baseballs were manufactured in Chicopee, Massachusetts....then Haiti, then Taiwan, back to Haiti in 1989. "Rawlings puts the Ball in Baseball. Most die-hard baseball fans are well aware that Rawlings has been the official and exclusive supplier of baseballs for Major League Baseball for over a quarter-century. They may even know that each Rawlings Official Major League Baseball (ROMLB) is made in Costa Rica.... Rawlings now produces 80,000 dozen ROMLBs annually at its Costa Rica plant this not counting baseballs made exclusively for the World Series, the All-Star Game and other special events such as the World Baseball Classic, etc.." Rawlings puts the Ball in Baseball | Think Blue LA
a. "MLBs strict specifications for the manufacturing of each ROMLB calls for a cork center (called a pill) that is wrapped in two thin rubber layers and weights exactly 7/8 oz. This pill is then machine-wound under consistent tension with 121 yards of four-ply blue-gray wool yarn, 45 yards of three-ply white wool yarn, 53 more yards of three-ply blue-gray wool yarn, and 150 yards of fine white poly-wool blend yarn.
... coated with an adhesive and two separate pieces of elongated figure-8-shaped white cowhide covers are placed on it. ... they are double stitched together by hand using 88 inches of 10/5 red cotton thread. It takes approximately 10 minutes to hand sew the 108 stitches into each baseball, with the first and last stitches completely hidden." Ibid.
4. Now, the ball must respond to the bat, to air resistance, and to gravity. If the bat provides an initial velocity of 110 mph, and assuming an angle of 35 degrees, it would travel about 750 feet.....in a vacuum. But in Yankee Stadium, about 400 feet, due to the density of the fluid, air, thorough which it must travel.
5. For a baseball passing through air at a velocity of less than 50 mph the air flow is smooth, but the air flow is turbulent for velocities greater than 200 mph. But, for the game of baseball, much of the ball's movement is in the range between 50 mph and 120 mph, and the movement of the ball depends on the surface of the ball and its motion. Get this: at a given velocity, the air resistance is less for turbulent than for smooth movement!
Adair, "The Physics of Baseball."
6. Baseball is a summer sport, and the density of the air itself doesn't vary much during that season. If one need discuss air density at all, remember how a barometer works. The more clear the day, the heavier the air...the higher the air pressure. This is due to the relative amounts of water versus oxygen in the air at any given time: a water molecule has an atomic weight of 18 AMUs, while oxygen weighs 32 AMUs. Most important in this discussion are drag coefficient, and velocity.
a. The drag coefficient is largely a function of the velocity, but the orientation of the stitches on the ball will alter it, as well. "Wind tunnel measurements reveal that the drag coefficient is a strong function of speed for baseballs, ..... At low speeds, the drag coefficient is approximately constant. However, as the speed increases, the drag coefficient drops.... for a completely smooth baseball the transition occurs at speeds well beyond the capabilities of the fastest pitchers. Conversely, the transition takes place at comparatively low speeds if the surface of the ball is rough. In fact, the raised stitches on the otherwise smooth regulation baseball cause the transition to occur at an intermediate speed which is easily within the range of major league pitchers."
Air drag
The baseball is not smooth.....the stitches, and their position, change it's motion.
You know where this is going....the trick is to make certain that the batter doesn't.
2. "1.09 The ball shall be a sphere formed by yarn wound around a small core of cork,
rubber or similar material, covered with two strips of white horsehide or cowhide, tightly
stitched together. It shall weigh not less than five nor more than 5 1/4 ounces avoirdupois
and measure not less than nine nor more than 9 1/4 inches in circumference." http://mlb.mlb.com/mlb/downloads/y2012/Official_Baseball_Rules.pdf
3. Once upon a time, baseballs were manufactured in Chicopee, Massachusetts....then Haiti, then Taiwan, back to Haiti in 1989. "Rawlings puts the Ball in Baseball. Most die-hard baseball fans are well aware that Rawlings has been the official and exclusive supplier of baseballs for Major League Baseball for over a quarter-century. They may even know that each Rawlings Official Major League Baseball (ROMLB) is made in Costa Rica.... Rawlings now produces 80,000 dozen ROMLBs annually at its Costa Rica plant this not counting baseballs made exclusively for the World Series, the All-Star Game and other special events such as the World Baseball Classic, etc.." Rawlings puts the Ball in Baseball | Think Blue LA
a. "MLBs strict specifications for the manufacturing of each ROMLB calls for a cork center (called a pill) that is wrapped in two thin rubber layers and weights exactly 7/8 oz. This pill is then machine-wound under consistent tension with 121 yards of four-ply blue-gray wool yarn, 45 yards of three-ply white wool yarn, 53 more yards of three-ply blue-gray wool yarn, and 150 yards of fine white poly-wool blend yarn.
... coated with an adhesive and two separate pieces of elongated figure-8-shaped white cowhide covers are placed on it. ... they are double stitched together by hand using 88 inches of 10/5 red cotton thread. It takes approximately 10 minutes to hand sew the 108 stitches into each baseball, with the first and last stitches completely hidden." Ibid.
4. Now, the ball must respond to the bat, to air resistance, and to gravity. If the bat provides an initial velocity of 110 mph, and assuming an angle of 35 degrees, it would travel about 750 feet.....in a vacuum. But in Yankee Stadium, about 400 feet, due to the density of the fluid, air, thorough which it must travel.
5. For a baseball passing through air at a velocity of less than 50 mph the air flow is smooth, but the air flow is turbulent for velocities greater than 200 mph. But, for the game of baseball, much of the ball's movement is in the range between 50 mph and 120 mph, and the movement of the ball depends on the surface of the ball and its motion. Get this: at a given velocity, the air resistance is less for turbulent than for smooth movement!
Adair, "The Physics of Baseball."
6. Baseball is a summer sport, and the density of the air itself doesn't vary much during that season. If one need discuss air density at all, remember how a barometer works. The more clear the day, the heavier the air...the higher the air pressure. This is due to the relative amounts of water versus oxygen in the air at any given time: a water molecule has an atomic weight of 18 AMUs, while oxygen weighs 32 AMUs. Most important in this discussion are drag coefficient, and velocity.
a. The drag coefficient is largely a function of the velocity, but the orientation of the stitches on the ball will alter it, as well. "Wind tunnel measurements reveal that the drag coefficient is a strong function of speed for baseballs, ..... At low speeds, the drag coefficient is approximately constant. However, as the speed increases, the drag coefficient drops.... for a completely smooth baseball the transition occurs at speeds well beyond the capabilities of the fastest pitchers. Conversely, the transition takes place at comparatively low speeds if the surface of the ball is rough. In fact, the raised stitches on the otherwise smooth regulation baseball cause the transition to occur at an intermediate speed which is easily within the range of major league pitchers."
Air drag
The baseball is not smooth.....the stitches, and their position, change it's motion.
You know where this is going....the trick is to make certain that the batter doesn't.
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