While learning about angular momentum in class my professor posed the question, "Why are their less left handed quarterbacks in the NFL than right handed?". He goes on to explain that in the case of a right handed quarterback the ball is given a clockwise rotation giving it angular momentum in the direction of its linear velocity (proven by the right hand rule) therefore increasing its velocity and increasing the possible distance thrown. Then he says that the left handed quarterback, who throws a counter-clockwise spiral, gives the ball angular momentum in the opposite direction of its linear velocity causes it to have a shorter trajectory. I simply could not believe this. It made no sense to me that the spin direction of the ball could effect its trajectory. (Assuming that each quarterback threw the ball exactly the same). I talked to him in order to get a better explanation and he basically just repeated himself. I've searched the internet for any material that may support this and have found nothing. I've even looked into the trajectory effects of the spin direction of bullets and found nothing. Could anyone explain to me why this is right/wrong?