A research balloon of total mass 'M' is descending vertically with a downward acceleration 'a'. How much mass 'm' must be thrown from the balloon to give it an upward acceleration 'a', assuming that the upward lift of the air does not change?

f=ma newton

f=100x2.5=250n

measuring things 1 litre of water

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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