9. Think and discuss: So far, you've been working with an “ideal" pulley system. How do you think real pulley systems are different, and how would that affect the mechanical advantage
of real pulley systems?

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

hope this ! this is not copied! search it up, it's free of plagiarism!