# Thread: [+fullrep] Science Help [light years/light seconds/scientific notation]

1. ## [+fullrep] Science Help [light years/light seconds/scientific notation]

"If 9.46x10^12 km = 1 ly, how many kilometers are there in 1 ls?"

Use GRASS method, and explain the reasoning behind your steps so I can understand it; basically you're teaching me this because my teacher made some dumbass in our class teach this to us.

2. I will be honest with you, I'm not exactly sure about the "GRASS" method you are talking about, but I'll try to explain it as best as I can.

Since you are going from light years to light seconds, you will divide by 365 to obtain the length in km of one light-day, by 24 to obtain the length in km of one light-hour, and by 3600 to obtain the length in km of one light-second.

Therefore, 9.46*10^12/365/24/3600 = 3.00*10^5 km per light-second.

Hope it helps!

3. ## The Following 2 Users Say Thank You to aznboy1997 For This Useful Post:

Mint (06-10-2013),wrath (06-10-2013)

4. OHHHHHHHHH I get it!

Thanks!

5. Originally Posted by aznboy1997
I will be honest with you, I'm not exactly sure about the "GRASS" method you are talking about, but I'll try to explain it as best as I can.

Since you are going from light years to light seconds, you will divide by 365 to obtain the length in km of one light-day, by 24 to obtain the length in km of one light-hour, and by 3600 to obtain the length in km of one light-second.

Therefore, 9.46*10^12/365/24/3600 = 3.00*10^5 km per light-second.

Hope it helps!
Leave it to an Aznboy right? I was looking at it, but I was always horrible with conversions. Thanks for explanation though, I was also curious.

6. ## The Following User Says Thank You to wrath For This Useful Post:

Mint (06-10-2013)

7. Originally Posted by aznboy1997
I will be honest with you, I'm not exactly sure about the "GRASS" method you are talking about, but I'll try to explain it as best as I can.

Since you are going from light years to light seconds, you will divide by 365 to obtain the length in km of one light-day, by 24 to obtain the length in km of one light-hour, and by 3600 to obtain the length in km of one light-second.

Therefore, 9.46*10^12/365/24/3600 = 3.00*10^5 km per light-second.

Hope it helps!
;____; I get 299,974.6322

8. Originally Posted by Mint
;____; I get 299,974.6322
He rounded it up and put it into scientific notation.

9. Originally Posted by Bettser
He rounded it up and put it into scientific notation.
I know I can look up how to turn stuff into scientific notation...but explain it to me?

10. Originally Posted by Mint
I know I can look up how to turn stuff into scientific notation...but explain it to me?
You know what rounding is so I dont need to explain that but for scientific notation:

You got 299,974.6322 as your answer. It looks quite tedious and simplified it looks like:

2.999746322 x10^5

If you multiply those numbers^, you get your original answer. Teachers normally want it to two decimal points so:

2.99x10^5 (Same answer, just more simplified)

Teachers also usually want the answer rounded to which arrives you at aznboy's answer.

3.00x10^5

11. Originally Posted by Bettser
You know what rounding is so I dont need to explain that but for scientific notation:

You got 299,974.6322 as your answer. It looks quite tedious and simplified it looks like:

2.999746322 x10^5

If you multiply those numbers^, you get your original answer. Teachers normally want it to two decimal points so:

2.99x10^5 (Same answer, just more simplified)

Teachers also usually want the answer rounded to which arrives you at aznboy's answer.

3.00x10^5
Wait, where did you get the exponent '5' from?

12. Originally Posted by Mint
Wait, where did you get the exponent '5' from?
By moving the decimal point

Example:
2.999746322 x10^5
29.99746322 x10^4
299.9746322 x10^3
2999.746322 x10^2

Are all the same as
299,974.6322

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