As you found out in the previous part, Bernoulli's equation tells us that a fluid element that flows through a flow tube with decreasing cross section moves toward a region of lower pressure. Physically, the pressure drop experienced by the fluid element between points 1 and 2 acts on the fluid element as a net force that causes the fluid to .

Increase in speed.

Explanation: Since mass must be conserved, if the cross section of the flow tube is not the same, that is varies, the flow speed must change to conserve mass.

This means that there is a non-zero net force acting on the fluid that causes the fluid to increase or decrease in speed depending on whether the fluid is flowing through a portion of the tube with a smaller or larger cross

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!