I hate to be the nerd in the bunch, but some of the math that Canoe referenced is wrong.
The speed of the arrow math works out well given gravity as a constant and you can figure out time by distance dropped etc...
However, when figuring out foot pounds the equation (arrow weight)/450*(arrow speed)^2 don't jive. That gives you foot ounces. You have to divide weight by 16 in addition to 450 (437.5 actually) to get foot pounds.
So the right function would be KE=(1/2)*[(arrow weight)/(437.5*16)]*(arrow speed)^2
Don't blame me, I'm an engineering student.
Edit: Me and my big mouth, forgot that KE=(1/2)mv^2. whoops