Many years ago, I became interested in calculating energy. Not so much now. Pretty much, it gets the job done or it doesn't.
Here is another link on Kinetic Energy. http://en.wikipedia.org/wiki/Muzzle_energy
I guess we payed someone to come up with this stuff. Not sure how they came up with the E=1/2MV squared idea.
I concluded at that time to leave out the whole "squared' thing and base energy solely on weight & velocity.
I figure it's like hitting a brick wall with a Half Ton Truck at 45 mph vs a VW at 90 mph. Which does the most damage. Better yet, which one achieved the predetermined goal?
What caused me to question the whole KE thing was when "someone" claimed that the 9 mm Luger had energy equal to the 45 acp.
Then came the debate about the 17 HMR vs the 22 Mag.
Back to my original thought, "does it get the job done?"
But I guess it doesn't hurt to have a reference to establish a starting point and adjust from there based on experience.
Or, just ask one of the members on the Marlinforum. We'll help get ya started.