Nemesis,

Rightly so!

If at the Handaq Range you where to tell us that your gun does 240m/s with .55gram pellets doing 15.40J we would just stare at you thinking WTF!  Is he trying to impress us or something  

Ok lets re-cap.
I tried to keep it simple so as NOT to look like we want to impress anyone.
The absolute kinetic energy formula is the simplest : E =1/2 x M x V x V
The answer will be in joules, because we are talking science not plebian and commercial convenience.

If you wish to convert Joules to Foot pounds: 1 Footpound = 1.356 Joules.

You can also convert your grians and feet per second to metric and  thereafter convert your Joules to foot pounds.

You can also use grains and feet per second direct using the  formula :   M v V x V / 450240
This will give you the Energy value in foot pounds right away.
If you look at this last formula you will still find the original 1/2 x M x V x V, but this time with the unit conversions built-in.


It sounds a bit complicated because we tried to "simplyfy" it.
The absolute is the simplest to understand and work with.

Luger, who is trying to impress?

I'm only still trying to learn here and impress no one.

Vincent thanks for helping me and sry if I'm bothering you.

But I think you didn't understand my last question.
You can't use the equation: M v V x V / 450240 for metric units (where M = Kg, V = m/s), can you?

Because I've tried to to work it out and the answers where completely different, even after conversion.

Is the constant number only applicable when using grains and ft/s?

OR

Should I use 1/2 x M x V x V when using metric units?

Thanks

Nemesis,

I was only pulling your leg mate.............you got no sense of humour? I always thought we put these    for a reason but I still tend to forget how sensitive people can be sometimes  

Anyways if I thought you were trying to impress with all these freakin equations to find out the muzzle energy of an airgun pellet then I would not have posted back trying to show which units are best when calculating stuff in the airgun field, which pellet is better and for what..................

Well I'm definetaly out of this thread now, seems like people around here still take things personally no matter how you try to put things for them unfortunately.................

PS...........regarding your last question, as far as I know you cannot use the constant 450240 to calculate joules but only when calculating foot poundage.

Over and out.....................

Luger, I'm sry but at that time I read the post I really didn't notice those similes. I took you a little bit seriously for a reason because in fact I'm not that sensitive.
The reason is that sometimes when I 'm asking about something just to learn it, some people tend to pull my leg all the time and end up with no info at all. Sometimes people thing that you're blufing or trying to learn the impossible. That's why I reacted to you post in that way, because I tought you where one of them. But anyway, I realized that you are not one of since you gave me some important info that I want to know.

Sorry mate & Thanks 

No problem mate, everything's forgotten 

Thing is that I tend to instinctively joke around or pull legs and very often I'm grossly misunderstood and taken personally. It has happened before over here and it almost happened again 

I can be serious when discussing airguns as you might have read in my earlier posts but some times the devil inside me just takes over 

Try and take it easy with the math regarding airgunning  In my opinion the only formula you need to know is - pellet velocity (fps) x pellet velocity (fps) x weight of pellet (grains) / 450240 = foot poundage (ft/lbs)

If you are used to metric units, yes I agree with you it might be a little confusing and frustrating at first but once you get used to it you will forget about metric units. Trust me............been there, done that 

Once you start chronoing your gun for velocities in fps, you will get used to calculating ft/lbs so much that just knowing the fps of the gun will be enough for you to mentally calculate roughly it's ft/lbs without using the formula! Not joking here!

Just my 2 pence! 

Nemesis,

Just remebered that I have an excel sheet which I use to convert anything you will ever need to convert in airgunning without having to use any math

Find attached............hope you find it useful mate 

this is easier.................http://www.airguns.net/calculators.php

And this has all the conversions under the sun...

http://www.simetric.co.uk

Thanks to all of you with your help. I really appreciate it.
And Luger, thanks for that spreadsheet. Its really practical and easy to use. In other words it's excellent. I'm gonna use it alot hehe
Besides for me, its still important to know how the formulas work for them(Which I finally understood), so thanks again for explaining to me how they work.

Thanks guys