Gravity made easy

Post by **aybraus** » Fri Nov 21, 2008 2:36 pm

1) Make a pole that is 8 inches tall and give it a flat base.
2) Attach an 8" chain to the end of it.

Now, when you want to know how fast something is rolling down a slope, you just put the base on the incline, then measure the distance between the pole and the end of the chain. That is how far the thing moves because of gravity. Wow!

EDIT: I KNOW WHEN I'VE BEEN BEAT.

Rody wrote:
IVhorseman wrote:You can also calculate the same distance by taking 8cos(angle)"! Hooray for too much physics!
wrong, the diagram shows what you get if you calculate 8tan(angle)

this is why I find his way to be wrong.
I'll post a picture of what I meant later.

EDIT: which is now.

as you can see this method DOES give you the 8sin(angle) which is the component of gravity we're interested in seeing.
even so, HIS method is a nice approximation, but only correct if the angle is really small.

Post by **Gorchek** » Sat Nov 22, 2008 1:38 pm

Nice! I'll have to keep that in mind.

Post by **Rody** » Sat Nov 22, 2008 1:45 pm

of course the chain has to be the same length as the pole is.
and maybe it is more accurate to use the distance from the end of the chain to the pole.

Post by **aybraus** » Sat Nov 22, 2008 6:26 pm

Rody wrote:of course the chain has to be the same length as the pole is.
and maybe it is more accurate to use the distance from the end of the chain to the pole.

No it should be longer or else it won't touch the ground.

Post by **Rody** » Sun Nov 23, 2008 9:23 am

does it have to touch the ground?
I kinda like my own interpretation, and I can make it work for angles up to 90 degrees.

Post by **warman45** » Thu Nov 27, 2008 7:14 pm

what your saying is like taking a piece of string and marking how far it is till it touches the floor?

Post by **pesgores** » Fri Nov 28, 2008 2:36 pm

OK...will it help in anything?

Post by **aybraus** » Tue Dec 02, 2008 5:09 pm

Post updated with "Helpful Diagram"

Post by **warman45** » Tue Dec 02, 2008 10:54 pm

diagram really helps

Post by **Bonn-o-Tron** » Tue Dec 02, 2008 11:00 pm

Strangely enough, that's almost exactly how I imagined it.

Post by **IVhorseman** » Wed Dec 03, 2008 2:33 am

You can also calculate the same distance by taking 8cos(angle)"! Hooray for too much physics!

Post by **Rody** » Wed Dec 03, 2008 11:07 am

IVhorseman wrote:You can also calculate the same distance by taking 8cos(angle)"! Hooray for too much physics!

wrong, the diagram shows what you get if you calculate 8tan(angle)

this is why I find his way to be wrong.
I'll post a picture of what I meant later.

EDIT: which is now.

as you can see this method DOES give you the 8sin(angle) which is the component of gravity we're interested in seeing.
even so, HIS method is a nice approximation, but only correct if the angle is really small.

Post by **RagnarokRose** » Wed Dec 03, 2008 1:50 pm

I really hate math.

This wont help much in actual battle situations. If the string only works at up to 45 degree angles, then the difference is almost to small to be noticed.

However, i don't see why it wouldn't work at degrees over 45 degrees. If the string is long enough, on a steep hill the vehicle would slide up to 5 inches - which can make a big difference.

Post by **Rody** » Thu Dec 04, 2008 5:34 am

that, is why I don't like his approach it kinda accidentally goes to infinite length if you go much too steep. (tangents do that you know)
my method however is accurate enough at all angles. (to about 90 degree's further than that you probably won't be sliding any more)

Post by **RagnarokRose** » Thu Dec 04, 2008 1:43 pm

90 degrees? Your vehicle is falling not sliding.

Correction to my last post, you can actually get a big movement going on a big enough angle.