chemistry
posted by aira .
Light travels at 3.00 x 10^8 m/s. If the starlight from the Unicorn galaxy takes 1 year 47 days and 2 hours to reach us. How far away is it in kilometers?

1 year=365 days
365 + 47=412 days total
412 days*(24hours/1 day)= 9,888 hours
9,888 hours + 2 hours=9,890 hours total
9,890 hours total*(60 min/1 hour)*(60 sec/1 min)= total time in seconds
3.00 x 10^8 m/s*total time in seconds= distance in meters
distance in meters*(1 kilometer/1,000m)= distance in kilometers 
9,890 hours total*(60 min/1 hour)*(60 sec/1 min)= total time in seconds
is 35,604, 000 right? 
Yes, 35,604,000 seconds, but what do you do with it once you have found the time that it takes in seconds?

I multiply 35,604,000 by 3.00 x 10^8 to find out the distance in meters?
which gives me 1.06812e+16??
is that right? 
You will get an answer that is very large, so you will have to use scientific notation. Report no more then 3 significant figures.

Yes, but only three significant figures. So, a number, decimal followed by two more numbers.

so it will look like this :
distance in meters (1.06)*(1 kilometer/1,000m) = distance in kilometers
> 0.00106 is the final answer? 
No, 1.06812e+16 is correct. But you are only suppose to report three significant figures: 1.07 e+16

yeah, but I'm very confused on how to get the final answer. Do i take 1.07e+16 and multiply it by a thousand to get km?

No. 1.07 x 10^16 is in meters; you have to take the whole thing and divide it by 1,000, not just 1.07.
So, 1.07 x 10^16 m*(1km/1,000m)= your answer in Km
****Notice how the m's cancel and you are only left with km.
The FINAL ANSWER SHOUD BE 1.07 x 10^13 
1,000meters=1km
So, you have to make this relationship a fraction.
1,000m/1km.
But how do I organize it in a way that meters goes away and kilometers remain?
(1km/1000m)
So if I multiply the ration this way, by my intermediate answer that is in meters, then the meters cross cancel and you are only left with meters.
I hope this makes more since. 
I GOT IT. thank you so much !! best tutor out here

You are too nice. At least you can understand my typos. When I help others on another forum, I can edit my answers, so I do not look like an idiot, but on this forum I can not.
Respond to this Question
Similar Questions

maths
the galaxy we live in is roughly lens shaped,and pins.its diameter is given inlight years. (1 light year=9.5Exp12km) calculate the circuference or our galaxy in kilometres. the earth is at a point 3Exp4 light yaersfrom the centre.How … 
algebra
A lightyear is the distance that light travels in one year. Find the number of miles in a lightyear if light travels 1.86 × 105 miles/second. (Round to one decimal place, and assume that there are 365 days in a year.) 
Astronomy
The apparent brightness of a Cepheid variable star in a faraway galaxy is measured to be 640,000 times fainter compared to an equivalent star 2,000 light years away from the Sun in our Galaxy. Assuming that there is no light absorption … 
Physical Science
Galaxy A is 600 million light years from earth. Galaxy B is moving away from the earth at a speed that is 80% as large as that of Galaxy A. How far from earth is Galaxy B? 
CHEMISTRY! HELP!
I have a hard time getting this someone help me? 
Physics
Our Milky Way galaxy is very similar to our neighboring galaxy Andromeda. Consider that each galaxy contains approximately 4.0 x 10^11 stars each star having an average mass of 2.0 x 10^30 kg. a. If the gravitational pull of Andromeda … 
Science need help ?????///
An astronomer observes two galaxies, A and B, which have redshifts of: Galaxy A = 0.020 and Galaxy B = 0.010. Which galaxy is closest to us and what is its distance away from us? 
science
In which of the following statement the word light year is used correctly? 
Algebra
A light year, the distance light travels in 1 year, is approximately 5.9×10^12 miles.A nearby galaxy is approximately 1.2×10^7 light years from our galaxy. Find the distance in miles between our galaxy and the nearby galaxy. IDK … 
Chemistry
How would I figure out how far the distance in kilometers between the sun and earth be if it takes 8.3 minutes for light to travel?