3A15.50 - Center of Percussion - Baseball Bat

Code Number:
3A15.50
Demo Title:
Center of Percussion - Baseball Bat
Condition:
Excellent
Principle:
Center of Percussion
Area of Study:
Acoustics
Equipment:
Bats, Pendulum, Pendulum support, and Sweet Spot Testing App.
Procedure:

Place the desired bat on the support with the correct length pendulum. They will swing in unison when the length of the pendulum is the same as the center of mass of the bat. This can be marked on the bat.

The center of percussion of the bat can be found by placing the bat into the testing apparatus using a balsa wood splint for the pivot. Lift the bat slightly and drop it onto the small block. If you have found the center of percussion, the balsa wood splint will survive intact. If not, there will be a torque on the end of the bat that will break the splint.

References:
  • Yau-Jong Twu, "From Rolling Without Slipping to Sweet Spots", TPT, Vol. 58, #3, Mar. 2020, p. 218.
  • David Kagan, "The Vibrations in a Rubber Baseball Bat", TPT, Vol. 49, #9, Dec. 2011, p. 588.
  • Dan Russell, "Swing Weights of Baseball and Softball Bats", TPT, Vol. 48, #7, Oct. 2010, p. 471.
  • Rod Cross, "A Double Pendulum Swing Experiment: In Search of a Better Bat", AJP, Vol. 73, #4, Apr. 2005, p. 330.
  • Rod Cross, "The Sweet Spot of a Baseball Bat", AJP, Vol. 66, #9, Sep. 1998, p. 772.
  • Howard Brody, "Models of Baseball Bats", AJP, Vol. 58, #8, Aug. 1990, p. 756.
  • H. Brody, "The Sweet Spot of a Baseball Bat", AJP, Vol. 54, #7, July 1986, p. 640.
  • Matt Goulet, "How a Major League-Worthy Louisville Slugger Gets Made", Popular Mechanics, Vol. 192, #7, July/Aug. 2015, p. 54.
  • D. Rae Carpenter Jr. and Richard B. Minnix, "M-694. Sweet Spot on Bat", DICK and RAE Demo Notebook, 1993.
  • Jodi and Roy McCullough, "Inertia with a Power Bat", The Role of Toys in Teaching Physics, p. 4.100.
  • Borislaw Bilash II and David Maiullo, "Standing Waves of a Baseball Bat", A Demo a Day: A Year of Physics Demonstrations, p. 214.
  • "The Sweet Spot on a Baseball Bat", The Caliper, Fall 2010, p. 9.
  • Jearl Walker, "1.23. Hitting a Baseball", The Flying Circus of Physics Ed. 2, p. 10.
  • Jearl Walker, "1.23. Hitting a Baseball", The Flying Circus of Physics, p. 10.
  • Harvard University Extension School, "Principles of Physics 1: Mechanics--Expt. The Sweet Spot".
  • Borislaw Bilash II, “A Sweet Bat“, A Demo A Day – A Year of Physical Science Demonstrations, p. 252.
  • Julius Sumner Miller, Q224 & A224, Millergrams II – Some More Enchanting Questions for Enquiring Minds, p. 69 & 117.












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