Stopped Bats and Rising Fastballs: .

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Thanks to J. J. Crisco & R. M. Greenwald Medicine & Science in Sports & Exercise 34(10): 1675-1684; Oct 2002. Corked Bats and Rising Fastballs: . Alan M. Nathan Department of Physics University of Illinois. Using Physics to Debunk Some Myths of Baseball September 23, 2006.
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On account of J. J. Crisco & R. M. Greenwald Medicine & Science in Sports & Exercise 34(10): 1675-1684; Oct 2002 Corked Bats and Rising Fastballs: Alan M. Nathan Department of Physics University of Illinois Using Physics to Debunk Some Myths of Baseball September 23, 2006

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Corked Bats and Rising Fastballs: Using Physics to Debunk Some Myths of Baseball October 27, 2004: the day the revile was broken

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References "Our objective is not to change the amusement but rather to comprehend it. "The physicist\'s model of the diversion must fit the amusement."

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References "The book is composed for the inquisitive layman… " "… numerous dubious claims about the diversion are tended to and… determined by this book."

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References Is this paradise? No, it\'s … . Iowa Dyersville, home of the Field of Dreams

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Outline How does a slugging stick function? The flight of a baseball. Leaving the no-turn zone. Assembling it all.

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Issues I Will Address What makes a difference more: pitch speed or bat speed? Is the ball "squeezed"? What/where is the "sweet spot"? Is plugging the bat successful? Does aluminum beat wood? Does a fastball rise? What\'s the arrangement with Denver? Can a curveball be hit more distant than a fastball?

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Champaign News-Gazette "You can watch a considerable measure by viewing" - Yogi Berra Easton Sports CE Composites

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When Ash Meets Cowhide A rough crash! constrains substantial (>8000 lbs!) ; time short (<1/1000 sec!) ball packs, stops, extends like a spring: motor vitality  potential vitality wasteful: loads of vitality disseminated bat draws back, vibrates bat pulls back, vibrates GOAL: expand batted ball speed ( BBS) BBS  105 mph, 30 o  d  400 ft each extra mph  ~5 ft

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What Determines BBS? pitch speed, bat speed, "impact proficiency" my exclusive recipe BBS = e v pitch + ( 1+e ) v bat average numbers: e = 0.2 1+e = 1.2 case: 90 + 70 gives 102 mph (~400") v bat matters considerably more than v pitch ! Every mph of bat speed worth ~6 ft Each mph of pitch speed worth ~1 ft

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What does e rely on upon? BBS = e v pitch + ( 1+e ) v bat 1. Weight and weight dispersion of bat Heavier bat more proficient bigger e; less backlash to bat Heavier bat has littler v bat (ordinarily) What is perfect bat weight? impact of bat weight on e is simple impact of bat weight on v bat harder

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Experiments to Determine v bat Use rapid video Measure reliance of v bat on … - bat weight W - "swing weight" or MOI Conclusion: MOI matters more than W Observation: Batters incline toward lighter bats—31-34 oz - control versus control

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Is There an Advantage to "Plugging" a Bat? In view of best exploratory information accessible: … for grand slam separate: no … for grand slam recurrence: possibly

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What does e rely on upon? 2. Bounciness of ball "coefficient of compensation" or COR 2 = bounce back ht/starting ht ~0.5 for baseball demo

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MLB specs Is the Baseball "Squeezed"? Is COR bigger than it used to be? Estimations with rapid gun COR=rebound speed/starting pace 1975 versus 2004 MLB rules permit ~ 10% scope of COR  35 ft 1975 and 2004 equivalent to few % No confirmation for squeezed ball

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What does e rely on upon? Affect area on bat: the "sweet spot" Minimize force to bat—at Center of Gravity Maximize bat speed—at tip Minimize vibrations which… sting! some of the time break the bat lessen COR  bring down BBS demos

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hubs CG The "Sweet Spot Zone" PC reproduction … which concurs with trials

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Vibrations and Broken Bats pitcher catcher motion picture

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Does Aluminum Outperform Wood? Aluminum has thin shell Less mass in barrel - bring down MOI, higher bat speed, simpler to control  - however less successful at exchanging vitality  - for some bats  scratchs off  simply like plugged wood bat "Circle modes" trampoline impact  "ping" demo

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The "Trampoline" Effect: A Simple Physical Picture Two springs commonly pack each other KE  PE  KE PE shared between "ball spring" and "bat spring" PE in ball for the most part scattered (~80%!) PE in bat for the most part reestablished Net impact: less general vitality disseminated ...and in this manner higher ball-bat COR … more "bob"— affirmed by test … and higher BBS Also found in golf, tennis, … demo

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Does Aluminum Outperform Wood? YES!

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Additional Remarks on e can be measured in the lab manage non-wood bats (NCAA, ASA, … ) "end conditions" don\'t make a difference Not even the player\'s hands!

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F Lift  F drag mg Forces on a Baseball in Flight Gravity Drag ("air resistance") Lift (or "Magnus") demo

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Effect of Drag and Lift on Trajectories F L (Magnus)  F d mg drag impact is tremendous lift impact is littler yet critical

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Some Effects of Drag Reduced separation on fly ball Reduction of pitched ball speed by ~10% Asymmetric direction: Total Distance  1.7 x remove at zenith Optimum grand slam edge ~30 o - 35 o

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F L (Magnus)  F d mg Some Effects of Lift Backspin makes ball rise "bounce" of fastball undercut balls: expanded separation, decreased ideal edge of homer Topspin makes ball drop "12-6" curveball topped balls plunge Breaking pitches because of turn Cutters, sliders, and so on

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F L (Magnus)  F d mg Does a Fastball Rise? Will a ball tossed evenly rise? Is there a net upward speeding up? Can Magnus compel surpass gravity? For this to happen… reverse-pivot must surpass 4000 rpm >25 upheavals not physically conceivable

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What\'s the Deal with Denver? High height, diminished gaseous tension 80% of ocean level Reduced drag Reduced lift Net impact: Fly balls travel ~5% more distant

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Oblique Collisions: Leaving the No-Spin Zone Oblique  f riction  turn Familiar Results: Balls hit to left/right break toward foul line Topspin gives dubious ricochets in infield Backspin keeps fly ball in air longer Tricky popups to infield demo

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Ball10 0 descending D = focus to-focus balance Bat 10 0 upward Undercutting the ball  reverse-pivot directions "vertical sweet spot"

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Putting it all Together: Can curveball be hit more remote than fastball? Bat-Ball Collision Dynamics A fastball will be hit quicker A curveball will be hit with more reverse-pivot

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Fastball with reverse-pivot Curveball: turn doesn\'t switch Curveball with topspin curveball can be hit with more reverse-pivot: WHY? Fastball: turn must switch Net impact: reverse-pivot bigger for curveball

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Can Curveball Travel Farther than Fastball? Bat-Ball Collision Dynamics A fastball will be hit speedier A curveball will be hit with more reverse-pivot Aerodynamics A ball hit quicker will travel more remote Backspin expands separate Which impact wins? Curveball, by a hair!

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Final Summary Physics of baseball is a fun use of essential (and not really fundamental) material science Check out my site on the off chance that you need to know more Thanks for your consideration and go Red Sox!

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