What two measurements do you need in order to calculate speed

Speed = (distance covered) / (time to cover the distance)

So you need to know the distance covered and the time it took to cover that distance.

the earths atmosphere is made up of nitrogen and oxygen. solids can turn into gasses through a process called sublimation. sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.

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