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Week of 7/5/99:
It's the heart of baseball season! First in a series of baseball questions!
Week of 7/5/99:
Q:
In 1852, Henrick G. Magnus made an extraordinary contribution to
baseball. Magnus was not a professional ball player, coach, team owner,
or even a sports writer. What did he do?
A:
German physicist Magnus reported that when a spinning
object (such as a baseball) moves through a fluid (air) it experiences a
sideways force. In the game of baseball, this force makes the spinning ball
curve when thrown by a skilled pitcher. This phenomenon is known as the
Magnus effect.
Congratulations to Stephen Jackson.
Specifically, the Magnus force pushes the ball at right angles to the direction
of flight and to the axis of spin. The Magnus force is responsible for the
curve of the curve ball and the "hop" of the fast ball. This force is a
result of an in-flight drag reduction on one side of the ball. When a
pitcher throws the ball with spin (on the order of 1600 revolutions per
minute for some pitches), the wake of the ball on the side that spins with the flow is largely
eliminated. The lower effective flow velocity on that side mimics low-speed,
attached flow and results in a large drop in the "form drag" on one side
of the ball (See the October '98 quiz
question on the aerodynamics of golf balls for an explanation of drag on
bluff bodies.). For you non-believers (and there were many back in the 1800s
who claimed baseballs could not curve), breaking ball hurler Freddy Goldsmith
threw a ball between three aligned vertical poles in New Haven in 1870.
Also, it is actually Lord Rayleigh who is credited with the first description
of the effect. Henrick Magnus reported it in his 1852 paper "On the
Derivation of Projectiles; and on a Remarkable Phenomenon of
Rotating Bodies." (G. Magnus, Memoirs of the Royal Academy, Berlin.)
- The Aeroquiz Editor
Week of 7/12/99:
It's the heart of baseball season! Second in a series of baseball questions!
Q:
Slugger Jim Thome of the Cleveland Indians is 225 pounds of hard hitting,
corn fed, Peoria brawn. His workout regimen likely includes a hefty
dose of weight training. Would you scoff at a claim that he could
exert over 8000 pounds of force? Why?
A:
The force applied to the baseball in a typical Thome home run swing
is about 8000 pounds, albeit for only one thousanth of a second!
Forces (impulses, more precisely) of these magnitudes are needed to
reverse the direction of a 90 mile-per-hour fastball towards the Jacobs
Field bleachers at about 110 miles per hour.
No one got the correct answer!
- The Aeroquiz Editor
Week of 7/19/99:
It's the heart of baseball season! Third in a series of baseball questions!
Q:
Section 1.10(c) of the Official Baseball Rules reads: "The bat handle,
for not more than 18 inches from the end, may be covered or treated with
any material or substance to improve the grip." Many of us remember the
famous "Pine Tar Incident" of 1983 involving George Brett of Kansas City and
manager Billy Martin of New York. With New York leading 4-3 in the ninth
at Yankee Stadium, Brett homered with two out and a man on to put the
Royals in front, 5-4. Billy Martin contended that Brett should be declared
out and the runs shouldn't count, because his bat had pine tar more than
18 inches from the knob. The umpires agreed, awarding the win to the
Yankees. The Royals protested, however, and league president Lee MacPhail
ended the Pine Tar Incident by overruling his own umpires and declaring
a resumption of play at a later date. Physically speaking, why are
baseball rulemakers worried about pine tar high on the bat?
A:
A ball hit with backspin can provide its own lift due to the Magnus
Effect (See 7/5/99's quiz for an explanation of this effect) and can travel
farther than a ball without spin. Some think that pine tar could enhance the
contact friction during a hit and create more backspin. Pine tar can also
hide "grooving" marks on the bat. A normal ball-bat collision, however,
ordinarily has enough friction to prevent the ball from "skidding" on
the bat while being hit. Batters who illegally coat or groove their bats
are not likely helping themselves.
What scandal would be complete without Billy Martin? Brett came
storming out of the dugout and had to be restrained by several other
men. Even though the game was supposedly over, the umpires tossed Brett,
manager Dick Howser, coach Rocky Colavito, and pitcher Gaylord Perry,
who tried to hide the bat, out of the game. Umpires were able to
confiscate the bat only because, as it was getting passed from Royals
player to player, the last man in the line didn't have anybody to
give it to.
Brett was the only player to win batting titles in three different
decades, a thirteen-time All-Star, and the last recent player to make a
serious run at hitting .400. He was inducted into the Baseball Hall of Fame
this week.
No one got the correct answer!
- The Aeroquiz Editor
Week of 7/26/99:
It's the heart of baseball season! Fourth in a series of baseball questions!
Q:
The range of speeds at which major league baseballs are thrown and
batted varies approximately from 50 to 130 miles per hour. Below
50 mph, the flow around the ball is entirely laminar; while above
about 150 mph, the flow can be considered to be completely turbulent.
The range of interesting baseball speeds occurs almost entirely within a
laminar-turbulent "transition zone." Why does this help make baseball
such a lively, unpredictable, and entertaining game?
No one got the correct answer. The question stands another week!
- The Aeroquiz Editor
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