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Main Boards => The Shooters FORM Board => Topic started by: Jeff Cooper on February 07, 2007, 01:15:00 AM

Title: Formulas for KE and stored energy in a bow
Post by: Jeff Cooper on February 07, 2007, 01:15:00 AM

Could someone please give me the formulas for figuring out KE in an arrow (I think it is mass X velocity squared divided by 450,240) And I really don't remember the formula for figuring out stored energy underneath the line on a force-draw-curve. Any help is greatly appreciated. Jeff Cooper

Title: Re: Formulas for KE and stored energy in a bow
Post by: sunny hill archer on February 07, 2007, 07:30:00 PM

Mass (in grains) multiplied by velocity (in feet per second) squared divided by 450240 equals KE in ft/lbs of force.

Title: Re: Formulas for KE and stored energy in a bow
Post by: Michael Harnage on February 08, 2007, 02:11:00 PM

Area under the force draw curve is just area. Area is length times width. Usually it's close enough to take 1/2 of the peak weight and multiply by the distance drawn. Then factor in the efficiency and you should get the same KE that arrow shows across the chrono.

Title: Re: Formulas for KE and stored energy in a bow
Post by: Jeff Cooper on February 09, 2007, 12:22:00 AM

Thanks guys.  What I am looking for is the formula to convert the area underneath the force draw curve into a useable number for ft-lbs of stored energy (SE), so I can compare my arrow's KE to my bow's SE in order to measure the bow's efficiency using different weight arrows...trust me, I do not get this technical for my everyday shooting...I just need to get through this science project. Again thanks to all who have or may respond...now it is back to the homework!

Title: Re: Formulas for KE and stored energy in a bow
Post by: AkDan on February 12, 2007, 03:02:00 AM

man that hurts, you didnt believe me ugg ON THE ke formula!

 If ya need help let me know, other then sledding tomorrow I'm wide open!!!!