If a star is located 40,000 light years from earth, what can you conclude about the light from the star?
answer

the light will travel 40,000 kilometers to reach earth.

the light will take 40,000 years to reach earth.

the light will travel 300,000 kilometers to reach earth.

the light will take 300,000 years to reach earth.

the light will take 40,000 years to get to earth :))

Explanation:

it was also right on the test gl! :33

the answer is b ) square root of 5

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.