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spudding equations

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spudding equations

Unread postAuthor: jonnyboy » Wed Apr 01, 2009 6:04 pm

Well I think something like this may have been posted like this a while ago but if I remember this is a little different.

The formula is h=vt - 16t^2 where h is height v is velocity and t is time. The 16t^2 is accounting for the gravity, as cleared up by rcman.

I know there's programs out there mainly the ones by d_hall but they are just estimates and don't account for some environmental factors although this equation doesn't account for anything it could be added in.

The main reasons I posted this is can you can find out the maximum height of a projectile and when it will get there. That may be useful for some things that can't be discussed here.

Really you just rearrange the equation to your liking to solve for your variable that you want to know. It's basic 8th grade math...

If you need help just ask.


:)
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Last edited by jonnyboy on Wed Apr 01, 2009 7:24 pm, edited 1 time in total.
mobile chernobyl wrote:I can shoot a Canuter Valve off my '82 Chevy Ram F150 AT LEAST 3/4 Mile with 'ma cannon made of soup cans duct taped together, then I just squirt some bacardi 151 in the chamber and hold up my cigarrete lighta and WHOOSH! That thing flies at least 3/4 mile
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Unread postAuthor: rcman50166 » Wed Apr 01, 2009 7:16 pm

Yes the 16 is only applicable to ft/s^2. It's -9.8 for m/s^2. The proper equation, as derived by Newton is D<sub>f</sub>=V<sub>i</sub>t+<sup>1</sup>/<sub>2</sub>at<sup>2</sup>+D<sub>i</sub>
D<sub>f</sub>=distance (m)
V<sub>i</sub>=initial velocity (m/s)
T=time (s)
a=acceleration (-9.8m/s<sup>2</sup>)
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Unread postAuthor: jonnyboy » Wed Apr 01, 2009 7:23 pm

Alright thanks for that info rcman! I'll edit my original post to reflect that. Although that formula gives me a headache:?
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mobile chernobyl wrote:I can shoot a Canuter Valve off my '82 Chevy Ram F150 AT LEAST 3/4 Mile with 'ma cannon made of soup cans duct taped together, then I just squirt some bacardi 151 in the chamber and hold up my cigarrete lighta and WHOOSH! That thing flies at least 3/4 mile
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Unread postAuthor: rcman50166 » Wed Apr 01, 2009 8:03 pm

Well theres still a bit more to it, In order to figure out how far it goes, you need to use that equation for the Y component of the velocity, which is found by using the equation: V<sub>y</sub>=V*Cos(angle)
V<sub>y</sub>=velocity in the vertical direction
V=muzzle velocity, or initial velocity
Cos=cosine
angle=angle that the projectile is launched at

You will also need to find the velocity in the X direction. That one is easy, its the first equation in the post two above this one except a=0.
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Re: spudding equations

Unread postAuthor: jimmy101 » Thu Apr 02, 2009 11:56 am

jonnyboy wrote:Really you just rearrange the equation to your liking to solve for your variable that you want to know. It's basic 8th grade math...

No it isn't. The posted formula ignores things that make a huge difference. Air drag for example. The difference bweteen what you calculate with that formula (which is only valid in a vacuum) is hugely different than the real world result.

You might take a look at http://www.inpharmix.com/jps/Hang_Time_vs_Muzzle_Velocity.html .

Edit: fixed link HTML
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Last edited by jimmy101 on Thu Apr 02, 2009 1:44 pm, edited 1 time in total.
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Unread postAuthor: Biopyro » Thu Apr 02, 2009 12:44 pm

Your link needs fixing Jimmy - the full stop at the end breaks it.
There is a Range calculator around which accounts for drag, wind, firing angle, local air pressure etc to give an accurate representation of speed from hang time/ distance or vice versa. I can't remember what it's called right now, but it's good, I'm sure I'll remember later if someone else doesn't.
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