Momentum is mass in motion. Direction is our use of it. The cannon ball has no momentum unless it is given energy the more you give it the farther it will go in what ever direction. Forcing it to go a certain direction is simply harnessing the momentum that is already there and using it. The straighter your arrow comes out of the bow the more momentum is focused. A sloppy barrel will not shoot a ball as far as a tight one. Wasted energy, but the same amount. Direction is not momentum. The better momentum is directed the more efficient energy is used.