Answer:
My full powers come when my makers are dead. I await a heavy hat to put on my head. What am I?
I help you carry your books.
The faster you run the harder it is to catch me
As a state in America I am round on both sides and high in the middle.
Goes over all the hills and hollows, Bites hard, but never swallows.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.