## anonymous one year ago Dimensional Analysis question A very large unit of measurement is the zettameter (zm). 1 zm = 1021 m, but astronomers measures distances in even bigger units called astronomical units (the au). One au is defined to be approximately 107 miles (the average distance between the center of the earth and the center of the sun). An even bigger unit is called the parsec, which is equal to about 2x105 au. When astronomers talk about intergalactic space however it’s even more convenient to use units of kiloparsecs. Given that 1.6 km = 1 mile, about how many kiloparsecs are there in a zettameter?

1. anonymous

Do you understand some of it?

2. anonymous

I got to go in 17min, so the more responsive you are, the faster we finish.

3. anonymous

Yes, the work I've came up with so far is, 10^18 km x (1mi/1.6 km) x (1au/10^7 mi ) x )1 Kiloparsec/2x10^8 au)

4. anonymous

I got 3 x 10^18 Kiloparsecs, but the answer key says the answer is 1/3 x 10^3 Kiloparsecs I don't know what I'm doing wrong

5. anonymous

the conversions should be 1 zm = 10^21 m 1 au = 10^7 mi 1 parsec = 2x10^5 au

6. anonymous

and so 1 kiloparsec= 2x10^8 au

7. anonymous

1000 parsec=1 parsec 1 parsec=2,00,000Au 1Au=107 miles 1zm=1021m

8. anonymous

Yes you right.

9. anonymous

10. anonymous

11. anonymous

is my setup wrong?

12. anonymous

its meant to be 10^21

13. anonymous

I converted 10^21 m to km, which is 10^18 km

14. anonymous

$\frac{ 1021m }{ 1 } \times \frac{ 0.001km }{ 1m } \times \frac{ 1mile }{ 1.6km } \times \frac{ 1Au }{ 107miles } \times \frac{ 1 parsec }{ 2\times10^5 Au } \times \frac{ 0.001 kiloparsec }{ 1 parsec }$

15. anonymous

ahh i forgot to convert parsec to kiloparsec thanks so much!!

16. anonymous

Ah, nice job attempting though!

17. anonymous

I have to go now. If you have any questions in 2 hours, I can help.

18. anonymous

alright thanks so much