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All 7th Grade Students Must Have Proof Of TDap Shot To Begin School on August 10, 2016.
Al hacer clic en la bandera en la parte inferior de esta página se traducirá este sitio web al español
New immunization requirements for the 2016-2017 school year/SB 277:áAll incoming Kindergarten and 7thágrade students must have current immunizations on record to begin school on August 10, 2016.áCalifornia law SB 277 no longer allows personal or religious beliefs exemptions. Clickáhere for more information.
CURRENT 6th Grade Students Must Have Proof Of Whooping Cough Immunization. Please submit proof of shot to school office by March 27, 2017
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Jennifer Krogman

Jennifer Krogman's Multimedia Blog

April 2009

Blog EntryBlog: Monday, April 27, 2009

Hey Batter Batter

Joel Zumaya of the Detroit Tigers is one of the fastest pitchers in baseball.  His fastball has been clocked at 104 miles per hour.  What does it take for a human being to send a 5 ounce ball whirling through the air at that speed?  Below are some of the motions and speeds required to pitch a baseball:

 

  • ARM ROTATION:  the average speed of arm rotation is 2,333 RPM
  • UPPER TRUNK ROTATION:  the maximum speed of trunk rotation is 400 RPM
  • PELVIS ROTATION:  the maximum speed of pelvic rotation is 200 RPM
  • BODY WEIGHT FORCE:  the average force with which the front leg comes down during the pitching motion is 175% that of body weight
  • BALL ROTATION:  the average rotational speed of the ball is 1,500 RPM

Try to locate each of the above motions in the following diagram:

Which motion do you think has the greatest impact on how fast a baseball will travel?  Which do you think has the least impact?  What do you think makes one pitcher able to throw the ball faster than another?

SOURCE:  Popular Science, August, 2008

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