The student had a conversation with an adult. The adult shared that when they were little, they remembered seeing tons of factories with smoke coming out of them. The students wondered what has changed in the community so that these factories stopped making heavy smoke come out of them. Why Don't We See Emissions Like This Too Often Anymore?

This photo (below) of a power plant was taken before carbon emission control equipment was added. Fossil fuel emissions are down since laws have been enacted to protect the air.

Most air pollutants come from burning fossil fuels or plant material. Some are the result of evaporation from human-made materials. Nearly half (49%) of air pollution comes from transportation, 28% from factories and power plants, and the remaining pollution from a variety of other sources.

What does the information from the article indicate?

There is no control over the amount of fossil fuel emissions.

Most air pollution comes from factories and power plants.

Laws against air pollution are working to decrease fossil fuel emissions.

Most air pollutants come for human-made materials being evaporated.

explanation:

the masses of the objects and the distance between them

d eras and periods

russian is not my first language, so i'm afraid i can't write out an answer in russian, but hopefully you can find a way to do so. here's my best translation of the problem: you're given a plot of a particle's position in one-dimensional space over time, and you're asked to find either the total distance traveled by the particle after 6 seconds had elapsed, or the total displacement of the particle after 6 seconds.

if you want the total distance traveled, you would first need to determine the particle's velocity as a function of time, then integrate that over the 6-second interval. we know the position function is quadratic with roots at 0 and 6, so we have

where is unknown. because the position is parabolic, there is symmetry about the midpoint at , and we know that

so that the position function is

which means the velocity is

then the total distance traveled is

so the total distance traveled is 20 m.

on the other hand, if you want to find displacement: the particle starts at and ends at , so its displacement is 0.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form