4. The lightest pilot-driven airplane ever built was the Baby Bird. Suppose the Baby Bird moves along the ground without a pilot at a speed of 88.0 km/h. Under these circumstances, the momentum of the empty plane would be only 2,790 kg • m/s. What is the mass of the plane?

Explanation:

mass x velocity

so i believe it'd be

2,790 x 88.0

but i could be wrong just an fyi

the most reliable source of information.is wikipedia

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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