Final answer:
Two unaccounted physical factors that could explain the difference in the launch speed of a ball are air resistance, which slows the ball down, and the angle of launch, which affects the trajectory and optimal speed attainment.
Step-by-step explanation:
When considering the difference in the launch speed of a ball, two physical factors that might not have been accounted for could be air resistance and the angle of launch. Air resistance can significantly affect the speed at which a ball travels, as it causes deceleration of the ball due to friction between the ball's surface and the air molecules. Meanwhile, the angle of launch plays a crucial role; a ball launched at an angle that is not optimal for the intended trajectory will not reach the maximum possible speed compared to a ball launched at the ideal angle for that specific situation.