Final answer:
The question about the VASI pertains to aviation and not physics. In the context of physics, the comparative graph would show declining vertical velocity for a ball thrown upwards until it stops and falls back. Positive slope denotes increasing value, negative slope indicates decreasing, and zero slope shows no change.
Step-by-step explanation:
The question 'How will the VASI look if you are approaching on the optimum glide slope?' pertains to aviation and not directly to the science of physics. However, to answer a similar physics-related question regarding the comparison of graphs of vertical velocity for each ball versus time, we would predict that a graph of a ball thrown upwards and affected by gravity would have a vertical velocity that decreases over time until it reaches zero at the peak of its path, at which point it would then start to increase in the negative direction as the ball falls back down.
This graph would show a positive slope as the ball rises, and a negative slope as it falls. In the presence of significant air resistance, the slopes would be less steep as the air resistance would slow the ball's ascent and descent, leading to a lower peak height and a slower return to the ground.
For Exercise A5, the appearance of a positive slope indicates an increase in the variable being measured over time; a negative slope indicates a decrease, and a zero slope indicates that the variable is constant over time. The comparison of these slopes is key in understanding the behavior of variables in a physical system.