In a previous section we looked at mixing problems in which the volume of fluid remained constant and saw that such problems give rise to separable equations. (see example.) if the rates of flow into and out of the system are different, then the volume is not constant and the resulting differential equation is linear but not separable. a tank contains 400 l of water. a solution with a salt concentration of 0.4 kg/l is added at a rate of 5 l/min. the solution is kept mixed and is drained from the tank at a rate of 3 l/min. if y(t) is the amount of salt (in kilograms) after t minutes, show that y satisfies the differential equation dy dt = 2 − 3y 400 + 2t . solve this equation and find the concentration after 20 minutes. (round your answer to four

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

there are two significant figures.

the transfer of heat by electromagnetic radiation is called thermal radiation . it is usually carried out by electromagnetic waves in an energy range just below the visible spectrum, which is the infrared range.

so the answer would be radiation.

: )

explanation:

two years ago, when picking flowers in the mountains back of yosemite valley, i found a book. it was blotted and storm-beaten; all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however; many of the inner pages were well preserved. and although all were more or less stained and torn, whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today; its granite pages have been torn and blurred by the same storms that wasted the castaway book.

two years ago, when picking flowers in the mountains back of yosemite valley; i found a book. it was blotted and storm-beaten, all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however, many of the inner pages were well preserved. and although all were more or less stained and torn; whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today, its granite pages have been torn and blurred by the same storms that wasted the castaway book.