# How is rolling ball physics set up?

**URL:** <https://forum.kirupa.com/t/how-is-rolling-ball-physics-set-up/109249>\
**Category:** Uncategorized\
**Created:** [May 3, 2004, 7:10pm UTC](https://forum.kirupa.com/t/how-is-rolling-ball-physics-set-up/109249 "2004-05-03T19:10:41Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![O\_M](https://avatars.discourse-cdn.com/v4/letter/o/848f3c/32.png) [@O\_M](https://forum.kirupa.com/u/O_M)\
**Post date:** [May 3, 2004, 7:10pm UTC](https://forum.kirupa.com/t/how-is-rolling-ball-physics-set-up/109249/1 "2004-05-03T19:10:41Z")

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Ive been looking around, but cant seem to find the formula described for a rolling ball slowing down including the gravity factor (9.81) a given friction and mass (kg). The surface would be 100% flat.

Does anyone know how it is set up? For instance in this example a ball rolling over the X axis in + direction (in other words degree 0 if im not mistaken)).

```auto

onClipEvent (enterframe) {
	if (!stop) {
		speed -= formula for slowing down;
		_x += speed;
		if (speed < 1) {
			stop = true;
		}
	}
}

```

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**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/kirupa/original/3X/6/2/621e5c11736f46532526e61be85940af4230f3e5.png) [@system](https://forum.kirupa.com/u/system)\
**Post date:** [May 5, 2004, 1:52pm UTC](https://forum.kirupa.com/t/how-is-rolling-ball-physics-set-up/109249/2 "2004-05-05T13:52:21Z")

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This one I guess: [http://www.kirupa.com/developer/actionscript/gravity.htm](http://www.kirupa.com/developer/actionscript/gravity.htm)

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<div class="post-metadata">

**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/kirupa/original/3X/6/2/621e5c11736f46532526e61be85940af4230f3e5.png) [@system](https://forum.kirupa.com/u/system)\
**Post date:** [May 5, 2004, 1:57pm UTC](https://forum.kirupa.com/t/how-is-rolling-ball-physics-set-up/109249/3 "2004-05-05T13:57:12Z")

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Yup. I imagine that if you take a look at a textbook definition of how gravity effects a rolling object, you could use the above tutorials as a basis to see how to get the effect you want…

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<div class="post-metadata">

**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/kirupa/original/3X/6/2/621e5c11736f46532526e61be85940af4230f3e5.png) [@system](https://forum.kirupa.com/u/system)\
**Post date:** [May 5, 2004, 1:59pm UTC](https://forum.kirupa.com/t/how-is-rolling-ball-physics-set-up/109249/4 "2004-05-05T13:59:43Z")

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Gravity DOESN’T affect a rolling object on a flat ground 🙂

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<div class="post-metadata">

**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/kirupa/original/3X/6/2/621e5c11736f46532526e61be85940af4230f3e5.png) [@system](https://forum.kirupa.com/u/system)\
**Post date:** [May 5, 2004, 2:19pm UTC](https://forum.kirupa.com/t/how-is-rolling-ball-physics-set-up/109249/5 "2004-05-05T14:19:41Z")

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…which is why I flunked physics. Twice.  
:beam:

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<div class="post-metadata">

**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/kirupa/original/3X/6/2/621e5c11736f46532526e61be85940af4230f3e5.png) [@system](https://forum.kirupa.com/u/system)\
**Post date:** [May 5, 2004, 3:03pm UTC](https://forum.kirupa.com/t/how-is-rolling-ball-physics-set-up/109249/6 "2004-05-05T15:03:50Z")

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😛

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<div class="post-metadata">

**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/kirupa/original/3X/6/2/621e5c11736f46532526e61be85940af4230f3e5.png) [@system](https://forum.kirupa.com/u/system)\
**Post date:** [May 5, 2004, 3:32pm UTC](https://forum.kirupa.com/t/how-is-rolling-ball-physics-set-up/109249/7 "2004-05-05T15:32:20Z")

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> [@Ilyas da Pom](#):
>
> Gravity DOESN’T affect a rolling object on a flat ground 🙂

I remember that from our Physics lessons in school 😉 (or whatever the correct name is)