Ablock slides along a path that is without friction until the block reaches the section l = 0.80 m, which begins at a height h = 2.5 m on a ramp of angle θ = 20 o . in that section, the coefficient of kinetic friction is 0.50. the block passes through point a with a speed of 8.0 m/s. if the block can reach point b (where the friction ends) what is the speed there, and if it cannot, what is its greatest height above a?

less than one you can't create energy

d. air pressure decreases as altitude increases.

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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