(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Using mass = 2.473x10^23kg and Density = 7.481g/cm^3 work out the radius of said sphere,

2. Relevant equations

D=M/V

4/3∏r^3

3. The attempt at a solution

D=M/V

DV=M

V=M/D

Mass = 2.473x10^23kg

V=2.473x10^23kg / 7.481g/cm^3

V=2.473x10^23kg / 0.007481kg/cm^3

V= 3.31x10^24 cm

V= 3.31x10^22 km

Vol of sphere = 4/3∏r^3

3√(3.31x10^22/(4/3∏)) = 19918033Km

I assume I have a massive problem in my calculations (I think theres a problem where i changed the 7.481g/cm^3 into 0.007481kg/cm^3) but I'm still pretty unsure about that one, since my answer at the end is in kilograms and the units i used when changing the decimal is in cm^3, I think that's my problem but i'm not sure)

Thanks

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Tried to change it into kg/km^3 and i got 2.473x10^23kg / 748.1

then cube-root((3.31x10^20)/(4/3Pi) to get 4291210 km, still unsure =/

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Changed it :

(2.473x10^23kg) / (7.481g/cm^3) into

(2.473 x 10^23kg) / (0.007481kg/cm^3) noting that it is CM(i remembered at the end ;) )

3.666622109x10^25cm <--- 4/3PiR^3

divide

3.666622109x10^25cm by 4/3Pi then

cuberoot to get:

206091073.4 CM(!) / 100 to get meters (=)

2060910.734 M / 1000 to get KM (=)

2060.910734 KM -

rounded to 2061km (4.S.F)

I hope that's right, it seems reasonably accurate,

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# Homework Help: Working out radius of sphere using Mass&Density

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