Ajet plane leaves the stratosphere and returns to the ground. how does the temperature outside the jet change during its descent through the troposphere?   a. it decreases and then increases.   b. it decreases steadily.   c. it increases steadily.   d. it increases and then decreases.

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

Suppose water is leaking from a tank through a circular hole of area ah at its bottom. when water leaks through a hole, friction and contraction of the stream near the hole reduce the volume of water leaving the tank per second to cah 2gh , where c (0 < c < 1) is an empirical constant. a tank in the form of a right-circular cone standing on end, vertex down, is leaking water through a circular hole in its bottom. (assume the removed apex of the cone is of negligible height and volume.) (a) suppose the tank is 20 feet high and has radius 8 feet and the circular hole has radius 2 inches. the differential equation governing the height h in feet of water leaking from a tank after t seconds is dh dt = − 5 6h3/2 . if the height of the water is initially 8 feet, how long will it take the tank to empty? (round your answer to two decimal places.)

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.