In a race, Usain Bolt accelerates at 1.99 m/s2 for the first 60.0 m, then

decelerates at -0.266 m/s2 for the final

40.0 m. How much time did the race take?

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.

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