# Hit baseball mph question

**URL:** <https://boards.straightdope.com/t/hit-baseball-mph-question/81120>\
**Category:** Factual Questions\
**Created:** [September 12, 2001, 6:21pm UTC](https://boards.straightdope.com/t/hit-baseball-mph-question/81120 "2001-09-12T18:21:50Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![justinh](https://avatars.discourse-cdn.com/v4/letter/j/9fc29f/32.png) [@justinh](https://boards.straightdope.com/u/justinh)\
**Post date:** [September 12, 2001, 6:21pm UTC](https://boards.straightdope.com/t/hit-baseball-mph-question/81120/1 "2001-09-12T18:21:50Z")

</div>

lets get to something else.

You see the radar guns on a pitch as 95 mph. but you never see the speed of a homerun hit off a 95 mph pitch. what is the mph of a ball that travels 400ft and lands 30ft up in the stands?

---

<div class="post-metadata">

**Author:** ![BobT](https://avatars.discourse-cdn.com/v4/letter/b/8e8cbc/32.png) [@BobT](https://boards.straightdope.com/u/BobT)\
**Post date:** [September 12, 2001, 6:46pm UTC](https://boards.straightdope.com/t/hit-baseball-mph-question/81120/2 "2001-09-12T18:46:43Z")

</div>

I’m no physicist, but that ball leaves the bat at a much faster speed than 95 mph. To hit the ball 400 feet, you have to generate a significant amount of bat speed.

If you have Adobe Acrobat reader and can make sense of this try:

[http://www.npl.uiuc.edu/~a-nathan/pob/collision.pdf](http://www.npl.uiuc.edu/~a-nathan/pob/collision.pdf)

---

<div class="post-metadata">

**Author:** ![rackensack](https://avatars.discourse-cdn.com/v4/letter/r/e5b9ba/32.png) [@rackensack](https://boards.straightdope.com/u/rackensack)\
**Post date:** [September 12, 2001, 10:21pm UTC](https://boards.straightdope.com/t/hit-baseball-mph-question/81120/3 "2001-09-12T22:21:40Z")

</div>

Professor Robert Kemp Adair of Yale University addresses this topic in his 1994 book _The Physics of Baseball_. I’ve read the book but don’t recall the specific answer myself; I want to say that the initial velocity is around 120-130 mph, but my recollection is very fuzzy.

---

<div class="post-metadata">

**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\
**Post date:** [September 13, 2001, 12:33am UTC](https://boards.straightdope.com/t/hit-baseball-mph-question/81120/4 "2001-09-13T00:33:55Z")

</div>

I have that book, and on p. 52 he says

> [@](#):
>
> Very large forces, reaching values as high as 8,000 pounds, are required to change the motion of the 5[sup]1[/sup]/[sub]8[/sub]-ounce ball from a speed of 90 mph toward the plate to a speed of 110 mph toward the center-field bleachers in the [sup]1[/sup]/[sub]1000[/sub] of a second of bat-ball contact