Home › Forums › Technical FAQ › How is kinetic energy calculated?
This topic contains 11 replies, has 9 contributors, and was last updated by djbowhunter 4 years, 3 months ago.

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Speaking of KE,,has anyone noticed a few articles in two different bow hunting mags. that have the KE formula at fps. fps. arrow weight then divide by 480,240.??Where did they get that # from ??.
Its probably a typo.
It was a typo. They have since corrected it with the correct constant of 450240………….VinceHere is a little explanation I typed up:
Symo, the calculator is an awesome posting… To bad we can download it and/or save it to our desktops… Thanks again for your helpful threads, links, videos, postings…
B.
Symo, the calculator is an awesome posting… To bad we can’t download it and/or save it to our desktops… Thanks again for your helpful threads, links, videos, postings…
B.
Thanks Symo, your calculator is awesome!
Someone remind me of *suggested* KE values for Big Game please.
I think elk is 55??I shoot my 570 gr arrows at 218 fps for 60 footpounds of KE , pull is 63 pounds.The calculator is awesome. Now all we have to realize is the KE that we calculate is at the bow and not down range. I need to get a stand up chrono to see what the actual energy is at the target for different arrow weights. Has anyone actually done this yet?The calculator is awesome. Now all we have to realize is the KE that we calculate is at the bow and not down range. I need to get a stand up chrono to see what the actual energy is at the target for different arrow weights. Has anyone actually done this yet?
i think rem tried that
You should add entry fields for elevation and latitude to get the acceleration of gravity correct. KineticCalc[/flash]
Here is a standalone version for your PC]KineticCalc.exe[/url:22okxhwk][/quote:22okxhwk]
hmm i would have explained it a little differently.if 1 lb mass = 7000 grains, then only the first conversion factor in the above equation would have been necessary, as the resulting units would have been those of energy (mass x speed squared).
i would have rather given the first conversion information as:
1 lb = 7000 grains
the second conversion factor is necessary because we must get pounds (a unit of force) into slugs (a unit of mass).
i would use the following for the second conversion factor:
32.174 lb = 1 slug
so everything together would be:
14,112,000 grain ft^2/s^2 x (1 lb / 7000 grains) x (1 slug / 32.174 lb) = 62.66 slug ft^2/s^2 = 62.66 ft lb
that’s just my take on it anyway
Thanks for the calculator, Please keep it available!!!!thank you. 
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