Answer:
First, as you may know, the light travels at a given velocity.
In vaccum, this velocity is c = 3x10^8 m/s.
And we know that:
distance = velocity*time
Now, if some object (like a star ) is really far away, the light that comes from that star may take years to reach the Earth.
This means that the images that the astronomers see today, actually happened years and years ago (So the night sky is like a picture of the "past" of the universe)
Also, for example, if an astronomer sees some particular thing, he can apply a model (a "simplification" of some phenomena that is used to simplify it an explain it) and with the model, the scientist can infer the information of the given thing some time before it was seen.
 
        
             
        
        
        
Magnets facing the same way  <span />
        
                    
             
        
        
        
First we gotta use an equation of motion:

Our vertical distance d= 100 m, initial vertical speed u = 0 m/s (because velocity is fully horizontal), and vertical acceleration a = 9.8 m/s2 because of gravity. Let's plug it all in!

Now we just need to solve for t:

Hit the calculators, and you'll get 4.5 seconds!
 
        
        
        
To find the total number of miles traveled by a person, we add the distance that he has traveled: 3.0 + 5.00 + 4.000. 
Now, to find the accurate number of significant figures when adding measurements, the basic rule for addition is to use the least number of decimal places when reporting the result.
Now, since 3.0 has the least number of decimal places, we report the sum with 1 decimal place and have 12.0 miles as the total distance traveled by the person to reach his destination.
Answer: 12.0 miles
        
             
        
        
        
Answer:
The answer is 3213.6 grams.
Explanation:
In meters the room dimensions are 3.05-3.2-6.86.
Total volume of the room is:

66.95 m3.
The density of carbon monoxide is 48 g/m3. Then total grams is present in a room measuring:
