# Baseball physics question **URL:** \ **Category:** Factual Questions\ **Created:** [January 25, 2019, 6:30pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409 "2019-01-25T18:30:39Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [January 25, 2019, 6:30pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/1 "2019-01-25T18:30:39Z")
It’s a Friday afternoon (here in NY) and I’m not asking a question about the Jewish religion! Seems like those questions always turn up during the Sabbath. Anyway, here’s my question: You have two batters, one is 100 lbs and one is 200 lbs. They both get the same weight bat up to the same speed when the ball contacts the bat. Same pitch, no air friction, etc. Does the ball go the same distance? What about if one the lighter batter has freakishly heavy arms and the heavier batter has light arm, so that their arms weigh exactly the same, but their total body weight is still 100 pounds different. Does that affect the ball distance? ---
**Author:** ![Jonathan\_Chance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jonathan_chance/32/701_2.png) [@Jonathan\_Chance](https://boards.straightdope.com/u/Jonathan_Chance)\ **Post date:** [January 25, 2019, 6:38pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/2 "2019-01-25T18:38:30Z")
I’m thinking either one would likely hit a strong single to GQ. Look at it go! ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [January 25, 2019, 6:41pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/3 "2019-01-25T18:41:24Z")
> [@Jonathan\_Chance](#): > > I’m thinking either one would likely hit a strong single to GQ. > > Look at it go! Man, I can’t believe I posted that in ATMB. Thanks for moving it! ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [January 25, 2019, 6:50pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/4 "2019-01-25T18:50:49Z")
Power is generated by the legs, transferred to the torso then through the arms. Imagine how far you could hit the ball if you stood still and just swung the bat with _only_ your wrists. It’s like cracking a whip. ---
**Author:** ![Barkis\_is\_Willin](https://avatars.discourse-cdn.com/v4/letter/b/a183cd/32.png) [@Barkis\_is\_Willin](https://boards.straightdope.com/u/Barkis_is_Willin)\ **Post date:** [January 25, 2019, 7:15pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/5 "2019-01-25T19:15:03Z")
If I understand the question correctly, you want to know if 2 different guys will hit a ball the same distance if literally the only variable is their weight. They generate the same bat speed, the pitch speed is the same, swing angle is on the same plane, both make contact on exactly the same part of the same bat. Distance is about exit velocity and there are a lot of variables that go into exit velocity. But weight of the guy swinging the bat isn’t one. So yeah, they’ll hit it the same distance. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [January 25, 2019, 7:50pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/6 "2019-01-25T19:50:54Z")
> [@Barkis\_is\_Willin](#): > > If I understand the question correctly, you want to know if 2 different guys will hit a ball the same distance if literally the only variable is their weight. They generate the same bat speed, the pitch speed is the same, swing angle is on the same plane, both make contact on exactly the same part of the same bat. Distance is about exit velocity and there are a lot of variables that go into exit velocity. But weight of the guy swinging the bat isn’t one. So yeah, they’ll hit it the same distance. Yes, that is my question. And I know that, for all practical purposes, bat speed is all that matters. But, this is a physics question, not a baseball question. I’m not saying you’re wrong, but does the momentum of the bat holder matter at all, even theoretically? Or, is the bat (and arms?) effectively decoupled from the body holding it? Would it then not matter if the batter let go of the bat an instant before it struck the ball (so the bat speed is still the same)? ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [January 25, 2019, 8:30pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/7 "2019-01-25T20:30:25Z")
[https://www.acs.psu.edu/drussell/bats/impulse.htm](https://www.acs.psu.edu/drussell/bats/impulse.htm) The inputs are just weights and speeds of the bat and ball. Essentially, the batter is only interesting in that he or she gets the bat up to speed. For a collision that lasts .7 milliseconds, the bat is essentially unanchored object. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [January 25, 2019, 8:48pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/8 "2019-01-25T20:48:01Z")
That’s what I suspected. Thanks for the cite! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 25, 2019, 8:56pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/9 "2019-01-25T20:56:39Z")
Speaking abstractly, the bat would be _almost_ like an unanchored object, but the batter is still exerting some nonzero force, and imparting some nonzero work, during the brief duration of the collision, so there would be some slight advantage to the bigger batter. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [January 25, 2019, 9:06pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/10 "2019-01-25T21:06:00Z")
> [@Chronos](#): > > Speaking abstractly, the bat would be _almost_ like an unanchored object, but the batter is still exerting some nonzero force, and imparting some nonzero work, during the brief duration of the collision, so there would be some slight advantage to the bigger batter. If he is also stronger. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [January 25, 2019, 9:19pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/11 "2019-01-25T21:19:15Z")
> [@CookingWithGas](#): > > If he is also stronger. Right. Let’s hold their strengths equal. All is equal except weight. ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [January 26, 2019, 2:19am UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/12 "2019-01-26T02:19:46Z")
In my mind, answering this question, I think about the following scenario: 1. A bat is swung to hit a pitch, but the mechanism holding the bat has a relatively loose grip, and, upon contact, the bat is knocked out of the grip. 2. A bat is swung to hit a pitch, and the mechanism holding the bat has a relatively strong grip, and, upon contact, the bat is firmly kept in the control of the mechanism and continues on the swing plane. In my estimation, the ball should go farther in 2 than in 1. That seems to indicate that, to the extent “power” is involved between our batters, the question is the ability of the batter to power the bat through the interaction with the ball. Weight alone won’t do that. ---
**Author:** ![MrKnowItAll](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrknowitall/32/87_2.png) [@MrKnowItAll](https://boards.straightdope.com/u/MrKnowItAll)\ **Post date:** [January 26, 2019, 3:05am UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/13 "2019-01-26T03:05:55Z")
I think all other things being the same (skill/power/pitch) the heavier player will hit it _slightly_ further, due to the fact the that the larger mass will resist being pushed backwards by the ball. The difference will be negligible. ---
**Author:** ![Ike\_Witt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ike_witt/32/283_2.png) [@Ike\_Witt](https://boards.straightdope.com/u/Ike_Witt)\ **Post date:** [January 26, 2019, 3:14am UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/14 "2019-01-26T03:14:22Z")
> [@DSYoungEsq](#): > > In my estimation, the ball should go farther in 2 than in 1. That seems to indicate that, to the extent “power” is involved between our batters, the question is the ability of the batter to power the bat through the interaction with the ball. Weight alone won’t do that. I’m not so sure. The notion of powerful athletes having ‘soft hands’ comes from somewhere. Golf instructors will tell you to just let the club sit in your hands rather than grip it. ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [January 26, 2019, 4:25am UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/15 "2019-01-26T04:25:17Z")
> [@MrKnowItAll](#): > > I think all other things being the same (skill/power/pitch) the heavier player will hit it _slightly_ further, due to the fact the that the larger mass will resist being pushed backwards by the ball. The difference will be negligible. Any energy that goes in to making the bat rotate after the collision is energy that doesn’t go into making the ball travel. The tighter a grip the batter has, or the heavier his forearms, the less energy is lost to the bat. But it also depends where the ball hits the bat. If the path of the ball at the point of contact passes through the CG of the bat, then the collision will slow the bat but won’t impart any force that causes it to rotate. In that case, the weight or grip of the batter doesn’t matter. ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [January 26, 2019, 5:50am UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/16 "2019-01-26T05:50:00Z")
> [@Ike\_Witt](#): > > I’m not so sure. The notion of powerful athletes having ‘soft hands’ comes from somewhere. Golf instructors will tell you to just let the club sit in your hands rather than grip it. A golf club is substantially different from a baseball bat (for reasons that should be obvious), and trust me, as one who has played golf for over 50 years, you don’t just let a club sit in your hands; it would fly out on the downswing, if not on the backswing or the follow through. :eek: ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [January 26, 2019, 10:50am UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/17 "2019-01-26T10:50:39Z")
> [@Telemark](#): > > [https://www.acs.psu.edu/drussell/bats/impulse.htm](https://www.acs.psu.edu/drussell/bats/impulse.htm) > > The inputs are just weights and speeds of the bat and ball. Essentially, the batter is only interesting in that he or she gets the bat up to speed. For a collision that lasts .7 milliseconds, the bat is essentially unanchored object. > [@Chronos](#): > > Speaking abstractly, the bat would be _almost_ like an unanchored object, but the batter is still exerting some nonzero force, and imparting some nonzero work, during the brief duration of the collision, so there would be some slight advantage to the bigger batter. I was amazed when I plugged in the equation but Chronos seems to be right, if the collision lasts .7 milliseconds and Google is right about the speed of sound in wood at \> 3000 m/s. The collision lasts long enough for the force from the grip to interact with the collision site. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [January 26, 2019, 1:26pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/18 "2019-01-26T13:26:55Z")
> [@Ludovic](#): > > I was amazed when I plugged in the equation but Chronos seems to be right, if the collision lasts .7 milliseconds and Google is right about the speed of sound in wood at \> 3000 m/s. The collision lasts long enough for the force from the grip to interact with the collision site. Does it last long enough to travel down the bat and arms to make the weight of the body matter? (I could probably do the math, but you seem to have the equations ready to go) ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [January 26, 2019, 1:37pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/19 "2019-01-26T13:37:28Z")
It does have enough time to interact with the body as a whole, but I don’t know if it would make the weight of the body matter, or just the strength. ETA: only barely since I’m assuming that waves travel through the human body at the same speed as through water, which is slower than wood. ---
**Author:** ![RaftPeople](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@RaftPeople](https://boards.straightdope.com/u/RaftPeople)\ **Post date:** [January 26, 2019, 5:54pm UTC](https://boards.straightdope.com/t/baseball-physics-question/828409/20 "2019-01-26T17:54:30Z")
Alan Nathan is a scientist that studies this stuff. Here’s an article he posted about the batter’s grip at impact has zero influence on the path of the ball (in summary: the wave generated by impact that travels to the knob of the bat and back to area of impact takes longer than the duration of impact): > **[The Grip Doesn't Matter](http://baseball.physics.illinois.edu/grip.html)** > > Alan M. Nathan, Professor Emeritus of Physics at University of Illinois and avid Boston Red Sox fan, presents important researchers in the history of The Physics of Baseball. [Next page](https://boards.straightdope.com/t/baseball-physics-question/828409.md?page=2)