# How can a thrown ball travel faster than a hand?

**URL:** <https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458>\
**Category:** Factual Questions\
**Created:** [October 31, 2012, 5:21pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458 "2012-10-31T17:21:25Z")\
**Posts on this page:** 10\
**Page:** 2

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**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\
**Post date:** [November 1, 2012, 3:13pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/21 "2012-11-01T15:13:58Z")

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A human punch, like a boxing punch, does not have the benefit of wrist rotation and finger extension. Compare simply tossing an object, like a shotput (analogous to a punch), with a baseball pitch (analogous to an atlatl).

The [atlatl:](http://en.wikipedia.org/wiki/Atlatl)

> [@](#):
>
> The throwing arm together with the atlatl acts as a lever. The atlatl is a low-mass, fast-moving extension of the throwing arm, increasing the length of the lever. This extra length allows the thrower to impart force to the dart over a longer distance, thus imparting more energy and ultimately higher speeds.

The pitcher’s arm and fingers act as a “fast-moving extension of the throwing arm, increasing the length of the lever.”

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**Author:** ![zombywoof](https://avatars.discourse-cdn.com/v4/letter/z/9e8a1a/32.png) [@zombywoof](https://boards.straightdope.com/u/zombywoof)\
**Post date:** [November 1, 2012, 3:34pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/22 "2012-11-01T15:34:00Z")

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> [@colonial](#):
>
> Even before rifling stationary firearms could shoot projectiles weighing  
> much more than a baseball at over 100 mph, so the speed of the emitting  
> body is not necessarily relevant at all.

In this case the gases behind the projectile (the actual source of propulsion) are moving at least as fast as it does when it leaves the barrel.

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**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\
**Post date:** [November 1, 2012, 3:39pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/23 "2012-11-01T15:39:45Z")

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> [@Gukumatz](#):
>
> humeral retrotorsion

Gesundheit.

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**Author:** ![drachillix](https://avatars.discourse-cdn.com/v4/letter/d/48db29/32.png) [@drachillix](https://boards.straightdope.com/u/drachillix)\
**Post date:** [November 1, 2012, 3:52pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/24 "2012-11-01T15:52:31Z")

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It is a series of combined movements that allows the accelleration of a baseball to pro speeds.

Think of it like throwing a ball forward from a moving car. The car is moving 40 mph and you throw the ball hard enough to go 30 mph forward. Briefly the ball itself is moving 70 mph.

A series of movements including hip pivot, shoulder rotation, arm extension, wrist movement, hand movement and finger movement.

This is not an actual breakdown, but more of an illustration

pivoting hips 10 mph  
shoulder rotation +25 mph  
arm extension +15 mph  
wrist pivot +10 mph  
hand movement +5 mph  
finger movement +10 mph

=75mph

Through training you can learn to optimize that flow of events to maximize pitching speed.

No cites beyond a discussion with a friend who was a relief pitcher for a AAA team for a couple years.

poor angle or technique at any point in the series removes a chunk of that speed. Pro pitchers are analyzed and drilled on how to optimize that

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**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\
**Post date:** [November 1, 2012, 4:30pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/25 "2012-11-01T16:30:47Z")

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> [@colonial](#):
>
> Even before rifling stationary firearms could shoot projectiles weighing  
> much more than a baseball at over 100 mph, so the speed of the emitting  
> body is not necessarily relevant at all.

Nor is your comment, unless you have exploding fists.

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**Author:** ![colonial](https://avatars.discourse-cdn.com/v4/letter/c/34f0e0/32.png) [@colonial](https://boards.straightdope.com/u/colonial)\
**Post date:** [November 1, 2012, 5:12pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/26 "2012-11-01T17:12:30Z")

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It’s time for Una Persson to solve the mystery for us.

> [@zombywoof](#):
>
> In this case the gases behind the projectile (the actual source of propulsion) are moving at least as fast as it does when it leaves the barrel.

> [@Really Not All That Bright](#):
>
> Nor is your comment, unless you have exploding fists.

W-e-l-l-l the projectile is not going to travel at any 100mph unless the energy  
from detonation is concentrated by the barrel, so I would consider the analogies  
to be something like:

barrel~pitcher’s fingers, and  
detonation~the rest of the pitcher’s body,

but hey, my only physics course was in Grade 9.

Google informs us that the formula for kinetic energy is:

KE = 1/2_M_V^2

Since energy depends on velocity \*squared \*I suspect that is part of the solution  
we are looking for.

Una! Help!

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**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\
**Post date:** [November 1, 2012, 5:51pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/27 "2012-11-01T17:51:06Z")

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Towards the release of the ball there is not a direct ‘solid’ connection between ball and hand. This can lead to a force multiplication almost like changing a gear ratio where the power of the hand is transfered into speed of the ball. This I believe would happen as the ball comes off the fingers, the ball would ‘roll’ off the fingers which imparts more speed then the hand it moving.

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**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\
**Post date:** [November 1, 2012, 6:14pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/28 "2012-11-01T18:14:45Z")

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A 90 mph fastball will have about 85ft# of kinetic energy. The longer the baseball is being accelerated the more energy will be imparted to it.  
I shoot arrows through a chrono while testing my bows. If I use an active bow hand, throw my hand forward upon release of the string I can add up to 20 fps to the speed of an arrow.

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**Author:** ![Learjeff](https://avatars.discourse-cdn.com/v4/letter/l/94ad74/32.png) [@Learjeff](https://boards.straightdope.com/u/Learjeff)\
**Post date:** [November 1, 2012, 6:36pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/29 "2012-11-01T18:36:37Z")

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> [@ZenBeam](#):
>
> The OP can try a simple experiment himself. Hold something in your hand and throw a punch, releasing it at the end. I did this with a dum-dum sucker (it being Halloween), holding the stick between my thumb and finger, and it went _poot_ on the floor about fifteen or so feet in front of me. Nowhere near where I could throw it with a level throw.

Right – we can’t equate the speed of the hand when punching with the speed of the fingers) when throwing a ball.

My money is on the claim that the hand is going 90 MPH when it releases the ball, and the ball never goes faster than the hand releasing it. (In the other thread I mentioned the possibility of the ball going faster due to spring effects. I do believe it’s possible for a tennis ball to leave the racket going faster than the head of the racket, and even faster than the strings where they contact the ball. But I doubt this is a factor in a baseball pitch.)

> [@Chessic\_Sense](#):
>
> Don’t forget to add the speed of the pitcher’s body. His whole body lunges forward, so there’s more velocity that just his shoulder-to-hand speed.

Good point, but that happens with the punch, too. It depends on the type of punch. For a boxer’s jab, which has to happen without a windup (that would ‘telegraph’ the punch), this is minimal. But I’m sure there are punches when one sees one’s opponent is stunned, and one gets a chance to really let fly. It’s not clear which kind of punch the 32MPH above is for.

> [@kanicbird](#):
>
> Towards the release of the ball there is not a direct ‘solid’ connection between ball and hand. This can lead to a force multiplication almost like changing a gear ratio where the power of the hand is transfered into speed of the ball. This I believe would happen as the ball comes off the fingers, the ball would ‘roll’ off the fingers which imparts more speed then the hand it moving.

I don’t buy this. The fingers could definitely flick at the release to impart more speed, but that’s still the body going the same speed as the ball, at release. How do we get any additional movement from the baseball by NOT touching it?

How can the process of imparting spin make the ball go faster (if as discussed above, the ball can’t convert rotational momentum into linear momentum – which I believe it can but not enough to matter here) ? If the ball is going faster than the fingers and rolls off them, that would slow it down, not speed it up.

There are definitely things in physics that are counter-intuitive. (Just hold a rotating wheel by its axles and impart a force to turn it, for example.) But if there’s anything special going on here, I want a much more specific and technical explanation, to be convinced.

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<div class="post-metadata">

**Author:** ![Learjeff](https://avatars.discourse-cdn.com/v4/letter/l/94ad74/32.png) [@Learjeff](https://boards.straightdope.com/u/Learjeff)\
**Post date:** [November 1, 2012, 6:40pm UTC](https://boards.straightdope.com/t/how-can-a-thrown-ball-travel-faster-than-a-hand/639458/30 "2012-11-01T18:40:50Z")

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> [@HoneyBadgerDC](#):
>
> A 90 mph fastball will have about 85ft# of kinetic energy. The longer the baseball is being accelerated the more energy will be imparted to it.  
> I shoot arrows through a chrono while testing my bows. If I use an active bow hand, throw my hand forward upon release of the string I can add up to 20 fps to the speed of an arrow.

Interesting, but I don’t think this is relevant.

The bow and arrow is a different case because energy is stored in the arch of the bow. Moving your fist has two effects: it can add energy to the spring (the arching of the bow), and it adds forward velocity. How does that apply to a pitching arm? Human muscles (unlike Kangaroo leg muscles) don’t store energy from an external source, like springs do.

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