## ChrisV 3 years ago The distance from Earth to the Moon is approximately 240,000 mi. The speed of light is 3.00 * 10^8 m/s. How long does it take for light to travel from Earth to the Moon and back again? Please Show work.

1. HawkCrimson

time from the earth to the moon = 240000m /(3.00*10^8)m/s time = .0008s therefore to the moon and back = .0016s

2. HawkCrimson

understand?

3. ChrisV

well its miles to meters

4. ChrisV

so first have to convert

5. HawkCrimson

oh ok ill fix it then thx

6. ChrisV

1 mi = 1609.34 m

7. HawkCrimson

kk

8. ChrisV

but i do understand what you did and thanks

9. ChrisV

this dimensional analysis stuff does not agree with me at times lol

10. HawkCrimson

ok then make the correction and it'll look like this time = 240000*1609.34/(3*10^8)

11. HawkCrimson

haha kk :)

12. HawkCrimson

n of course multiply the answer by 2

13. ChrisV

you could just begin with 480000 right?

14. HawkCrimson

yea u could just because its doesnt throw off the working

15. ChrisV

480000 mi * 1609.34m/mi * s/300000000

16. ChrisV

300000000 m oops

17. HawkCrimson

if this is home work then you shouldnt multiply by 2 first actually cause yes you'll get the rigt answer but when u write ur statements u'll have to explain y u muliplied by 2 n it makes more sense to do it after

18. ChrisV

i still get the wrong answer i think >.< i get 2.57 s

19. HawkCrimson

yea that is the correct answer

20. ChrisV

(4800000 * 1609.34)/300000000 = 2.57s

21. HawkCrimson

yep

22. ChrisV

k thanks a ton

23. HawkCrimson

sure thing :)