Arrows don't fly particularly fast. Bullets on the other hand do. Typically a bullet leaves the barrel around 2800 fps and weighs around 150 grains. There are 7000 grains to the lb. Energy is mass x velocity of course.
However, arrows weigh a lot. They're weighed in ounces, not grains. All of that moving energy if concentrated on a tiny tip and as arrows don't usually expand on contact, they are the same diameter all the way down so they slip through and out the other side. All of that comedy stuff where people have arrows sicking out of them is hooey. They even go through armour. For what the lack in range and level flight, they make up for in closer distance penetration. I wouldn't stand in front of one.