Water is supplied to the atmosphere by evaporation from the surface, and leaves the atmosphere via precipitation. the average amount of time a water molecule spends in the atmosphere can be derived by dividing the amount of water vapor in the atmosphere (1.1x1016 by the globally-averaged rate of precipitation to the earth’s surface of 3.1 mm −1 . using these data, calculate how many days, on average, a water molecule spend in the atmosphere before it precipitates out.

f=ma newton's second law 7x8=56n

the area between the graph and the t axis

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

answer: 31, 5556. 952 seconds