Converting light years to meters and miles

AI Thread Summary
A light-year is defined as the distance light travels in one year, which is approximately 9.46 x 10^15 meters. To calculate this, one must first determine the number of seconds in a year and multiply that by the speed of light, 3.00 x 10^8 m/s. The conversion from meters to miles can be achieved by dividing the meter value by 1609. The discussion highlights confusion around the calculations and emphasizes the correct approach to find the distance in both units. Ultimately, understanding the relationship between time, speed, and distance is crucial for solving the problem accurately.
TrimHopp
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Homework Statement



A light-year is the distance that light travels in one year. Find this distance in both miles and meters.

Homework Equations



Speed of light (c) = 3.00x10^8 m/s

The Attempt at a Solution



10^15 m/s
__________
3.00x10^8 m/s

That is to find meters...I think I can only find miles after I find meters by dividing that answer by 1609m

Thanks.
 
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I think google could help you with this.
 
TrimHopp said:

Homework Statement



A light-year is the distance that light travels in one year. Find this distance in both miles and meters.

Homework Equations



Speed of light (c) = 3.00x10^8 m/s

The Attempt at a Solution



10^15 m/s
__________
3.00x10^8 m/s

That is to find meters...I think I can only find miles after I find meters by multiplying that answer by 1609m

Thanks.

Where did 1015 m/s come from? and what are you doing/trying to do?

You were told how far light goes in a second, how about a minute? Then how about an hour? a day? 365.24 days? [a year]

Once you know how many meters, I wouldn't be multiplying by 1609. I don't think anything is more miles away from something that it is meters away from something! The end of my street is about 120 m away, but it is far less than even 1 mile.
 
Right peter, I meant divide. Thanks for that.

In the book where I get the problem from, it says 1 light year = 9.46 Pm (P being peta (15) and m being meters). I thought that was 10^15?
 
TrimHopp said:
Right peter, I meant divide. Thanks for that.

In the book where I get the problem from, it says 1 light year = 9.46 Pm (P being peta (15) and m being meters). I thought that was 10^15?

Yes, but then that makes the length of a light-year 9.46 · 1015 m. But if you know this, why divide by the speed of light? That would tell you the length of time it takes light to travel one light-year, yes?

You are being asked to compute the length of a light-year, given that light travels at (very nearly) c = 3.00 · 108 m/sec . You need to work out the number of seconds in a year. (You may use the distance you looked up as a check...) You then need to convert this value from meters into miles.
 
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