# A2 physics

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#1
Help!!!!!! Don’t understand how to convert s-1 to kms-1Mpc-1 for part 1 I understand how to get the Hubble constant. For part two I don’t understand the last bit why they added 7.80 to 656
Last edited by Danyal124; 4 months ago
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4 months ago
#2
For part 2 you know that the galaxy is probably moving away. Assuming this, the light will be redshifted (i.e. the observed wavelength will increase and the frequency will increase.) So once you’ve figured out the change in wavelength, since you know the wavelength gets bigger, you add this to the original wavelength.
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4 months ago
#3
For the conversion, for example when converting from m to km, you divide by 1000, as you are multiplying by k. Likewise , to convert to km s^-1 Mpc^-1 you divide by 1000(m for the km) and multiply by how many metres are in a mega parsec (parsec is given, so you just multiply this by 10^6 for mega). Hope this helps
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