torque and punching bags

This weekend, i was with my brother when he was working out hitting the punching bag. When he was hitting the bag i noticed that the bag swung more or less depending on the place he hit the bag. This reminded me of the torque equation that we learned on friday which is torque equals force times lever arm. The force that my brother was hitting the bag at is about the same no mater where he hits the bag. But the lower he hit the bad the further it traveled. this is because the axis of rotation is above the bad where the chain is mounted to the ceiling. The lower he hits the bad the longer the lever arm is. A longer lever arm with the same force increase the amount of torque. The net force of the torque translates into angular acceleration of the bag making it rotate up. The lower he hit the bag the more torque and the greater amount of angular acceleration. Another thing i noticed is that he always hit the bag perpendicular to the lever arm. This maximizes torque because only a compenet of the force applied transfers into torque. If he were dumb and hit the bag at the hinge, the will be no torque and angular acceleration because the lever arm is zero. If he were to hit the bag directly underneath and straight up toward the hinge he there will also be no torque and angular acceleration because there is no component of force perpendicular to the lever arm.