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## Discussion: A Question 4 U Bat/Math Geeks

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Nov. 27 Home Plate 35 posts | A Question 4 U Bat/Math GeeksHi Before I ask my question, I want you to know that I have worked the problem and got an answer, but I'm not sure I got the CORRECT ANSWER. The last time I did any math of this sort was well into the last century. I also took "French" back then and can't remember any of it. Getting older and not using what I learned way back when has made me forget stuff. Anyway, on to the question: I have 2 bats of the same make and model with the only difference being one bat is 28 ounces and the other 26 ounces. If I swing both bats at the same speed 75 MPH Calculate how much difference will the ball exit speeds be between the 2 bats? What answer did you get? Thanks... |

Nov. 27 coop3636 516 posts | A Question 4 U Bat/Math GeeksThe difference is A pop up to the catcher or a pop up to the pitcher... That's why I use a 27 oz bat..lol |

Nov. 27 Dbax Men's 65 2113 posts | A Question 4 U Bat/Math GeeksI'll make a guess and say they will be the same. |

Nov. 27 DaveDowell Men's 70 4387 posts | A Question 4 U Bat/Math GeeksThis sounds a lot like the grade school math quiz: "Two trains are on the same track at a distance of 100 miles apart heading towards one another, each at a speed of 50 MPH. A fly starting out at the front of one train, flies towards the other at a speed of 70 MPH. Upon reaching the other train, the fly turns around and continues back towards the first train. How many miles does the fly travel before getting squashed in the collision of the two trains?" ... I can't figure that one out either! |

Nov. 27 AJC Men's 60 222 posts | A Question 4 U Bat/Math GeeksDave, that's 1 fast fly. I'd have to say since both trains would have met at the 50 mile mark the fly flew a distance of 70 miles, providing of course he didn't stop anywhere along the way to rest. |

Nov. 28 Crusher23 Men's 55 53 posts | A Question 4 U Bat/Math GeeksIt's a trick question, there's, not enough information to come to a conclusion here. Bat weight and swing speed are only 2/3 of the necessary information to be able to figure this out - you also need to know the distribution of the weight in each bat. This is important, as from what I can gather this is used to calculate something called Moment of Inertia, which from what I can tell from my limited physics exposure comes down to how much force is transmitted to the ball at the moment of impact with the bat. It is very possible that if each bat is swung at the same speed that the 26 ounce bat may transfer more force to the ball and thus produce a greater exit speed if it is end loaded enough and the 28 is balanced. That's as far as my physics knowledge goes boys. Hek, I'm probably wrong anyway but if you think about it, it makes sense. I do not know the actual equation to figure all this out, I'm sure it's on the web somewhere. |

Nov. 28 Home Plate 35 posts | A Question 4 U Bat/Math GeeksCrusher23 OK...Just for sake of conversation let's use Adidas End load bats. I would think any same Make and Model, be it Mikens, Combats or any other bats would work. After all everything is exactly the same (bat speed, the ball, the ball pitch speed, temperature and any other factors) except for the different weights of the bats compared. I think the MOI has a formula that applies. Thanks for your input... Anyone that can provide info...Thank you |

Nov. 28 Crusher23 Men's 55 53 posts | A Question 4 U Bat/Math GeeksMy apologies. I need to read my test questions more carefully. It did indeed state "2 bats of the same make and model with the only difference being one bat is 28 ounces and the other 26 ounces" It's going to be a rough next couple of decades for me if this keeps up... |

Nov. 28 B94 Men's 50 138 posts | A Question 4 U Bat/Math GeeksThe answer will depend more on what bat speed you carry through the point of contact. The bat you lose the least amount of speed with will be the bat that generates the better exit speed... |

Nov. 28 Turbo 34 Men's 50 47 posts | A Question 4 U Bat/Math GeeksIf you swing both bats the same exact speed, 75mph, the heavier bat will always hit the ball further. The shells of the two bats would weigh exactly the same. The 28 would have MORE end load even if both are end loads or balanced. However, it's very doubtful you would be able to swing the 28 as fast as the 26 if both bats are the same model as you stated. It's highly probable you would swing the 26 at least 10 mph faster which changes the equation and which bat slows down more on impact. No way possible a 28 will slow down at impact more than a 26 if impact speed (75mph) of both is the exact same. Force = Mass x Acceleration. Newton's Second Law of Motion. |

Nov. 28 Home Plate 35 posts | A Question 4 U Bat/Math GeeksTurbo 34 If you swing both bats the same exact speed, 75mph, the heavier bat will always hit the ball further.... And my question is: HOW MUCH FARTHER? |

Nov. 28 taits Men's 65 4546 posts | A Question 4 U Bat/Math Geeksimo, Since no two people let alone a group like here can hit consistantly at the same bat speed rate each time or with same power, you answer would be... depends on person at that time and other external forces prevailing at the time ball was hit. |

Nov. 28 fennellwg Men's 60 97 posts | A Question 4 U Bat/Math GeeksAbout 10 mph of BBS or 20 ft xtra distance. No reason for you to believe ..... But, by the time you are ready to disprove it, you will need to supply or assume values to all of the variables you are willing to say don't change from one bat to the next. http://www.acs.psu.edu/drussell/bats/bat-regulate.html Check out this link above used by the grownups that certify bats for senior play. Let me know what you think. We can start filling in some of the blanks or revise the question to better fit what you may want to know. Regards, Bill |

Nov. 29 fennellwg Men's 60 97 posts | A Question 4 U Bat/Math Geekshttp://www.acs.psu.edu/drussell/bats/bbs-asa.html Another good article by da Russell describing experimental process to regulate potential peak exit speeds of ASA bats. Both articles use assumption of conservation linear and angular momentum along with conservation of energy to develop a relatively simple equation that predicts batted ball speed (BBS) The unknowns are the relative collision efficiency of bat and ball. COR stamped on a softball is related to the contribution of the ball to the efficiency term. The combined efficiency term is measured experimentally by firing a softball at a stationary . Recording in/out speed of both ball and bat provides combined collision efficiency (BBCOR). ........... Regardless of the above , a couple of things that most smart folks have already figured out. 1) if you swing two bats at the same speed, the bat with the highest moment of inertia (MOI ) will provide the most momentum to the collision and yield best BBS and distance potential. 2) in general, your ability to generate max bat speed is a direct function of MOI the greater the inertia of the bat the slower your peak speed. However, the specifics vary from person to person. 3) I would assume that two " identical " bats that differ only by their total weight also have different MOI with associated impact on swing speed and batted ball speed. However, it's possible to have a heavier bat with lower MOI, even if you think they are the same flavor. Manufacturers seldom tell you, but it's a relatively easy number to measure. Regards, Bill |

Nov. 29 fennellwg Men's 60 97 posts | A Question 4 U Bat/Math GeeksOne final comment. Bats with higher MOI tend to have higher collision efficiency . Balls hit at higher speeds then to have lower collision efficiency. So, if distance and BBS are your priority metrics, the "heavier" bat may perform better despite a nominal loss in bat speed. Disclaimer.... your mileage may vary. |

Nov. 29 fennellwg Men's 60 97 posts | A Question 4 U Bat/Math GeeksYikes, too much typing to hold anyone's attention. In short,....I agree with Turbo 34 |

Nov. 29 Home Plate 35 posts | A Question 4 U Bat/Math GeeksWow! That's a lot of information to digest. I find it interesting that a 2 ounce bat weight gain gives the ball an extra 20 feet flight, which is a very significant distance. My calculations were about half of yours. It appears that every ounce of bat weight gain give about 10 feet distance on average. I think you did a fine job of explaining your answer to my question. Thank you much.. |

Nov. 30 fennellwg Men's 60 97 posts | A Question 4 U Bat/Math Geekshttp://baseball.physics.illinois.edu/aero.html If you're still interested, this is a pretty cool site by Alan Nathan This particular page Links to a spreadsheet that computes ball trajectory/ distance . It allows you to play with a bunch of different input variables like Launch angle, air density, temperature, humidity, spin rate, ball weight and diameter. You still need to estimate BBS as an input, but all the potential " what ifs " are fun. Bill |

Nov. 30 OZ40 550 posts | A Question 4 U Bat/Math GeeksYour answer can be found here if anywhere: http://engineering.mit.edu/ask/index.php MIT answers questions from us regular guys, keep us posted! |

Dec. 1 fennellwg Men's 60 97 posts | A Question 4 U Bat/Math GeeksI suspect the kids from MIT could do a pretty good job with this. But face it, they have more important things to do than predict numbers for a girls sport played by old men....besides they don't play any sports anyway. On the other hand, all of the math I pilfered come from places like penn state, SMU, and Wash State where baseball is a big budget item. So who do you think has the motivation to get this right? To HOME PLATE ... if you'd like a copy of my spreadsheet calc with assumptions and equations, feel free to send me your email address Bill FennellwgATverizon.net |

Dec. 2 the car 83 posts | A Question 4 U Bat/Math Geeksbat speed is bat speed if it hits the sweet spot same only if the walls of the bat are the same |

Dec. 3 fennellwg Men's 60 97 posts | A Question 4 U Bat/Math GeeksI agree. Batspeed has much greater effect on BBS than pitch speed. Swinging a bat at 75 mph off a Tee is likely to produce 50% higher BBS when compared to swinging 50 mph at a ball with pitch speed of 25 mph. perhaps a useless factoid, but on a more practical level..... It's hard to separate the effect of batspeed and bat inertia. The combined product of speed x mass generates the momentum that powers a softball collision. What do you do if you cannot swing your 28 oz as fast as your 27 oz? History suggests that the increased inertia of a heavier bat will reduce your batspeed. However, if you are able to maintain batspeed within a nominal value like 3-5 mph, I believe the bat with largest rotational inertia (MOI) will hit produce longer hits. IMO, Bill |

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