Lot to Learn,
here is an article that I found particuarly interesting. It takes the physics of arrow flight and breaks it into easy to understand terms. Some may a differing opinion with the entire light vs. heavy debate, but it's difficult to disagree with the physics of the equation.
One area to be cognizant of, the faster an object, the more force (air resistance) slowing it down. An arrow going 350 fps, slows down at a faster rate than an arrow going 300 fps all else equal (arrow diamater, etc). Another area to consider is that because a faster arrow slows down at a quicker rate, you are at some point (distance wise) going to reach a break even point. When a bow is rated for speed, it's typically rated at point blank range as the speed of the arrow slows down the further down range you get. I doubt many of us shoot deer at point blank range with our bow.
Bottom line, it's a delicate balance of speed and arrow mass (weight) that we must maintain, with an edge to the mass side of the equation. Either extreme is not desireable per most archers. On one hand, being overly fast can create more bow noise (negative) and a flatter trajectory (positive), but on the other hand, shooting too heavy of an arrow means a quieter bow (positive) but an increased importance on accuracy --lobbing trajectory (negative). I don't care how heavy the arrow is, if your lobbing it in like a football hail mary, chances are the animal will have an opportunity to move and KE doesn't mean a whole lot when you've missed the animal.
http://archeryreport.com/2010/04/heavy- ... eed-power/