The base units of the Gravitational Constant 'G'?

[rindishy123]

Hi.

Part of my homework was to work out what the SI base units of the gravitaional constant are.

I'm crap at working out base units so could somebody help me out?

Thanks

If anyones wondering, G is 6.67 x 10ˉ¹¹ N m² kgˉ²

 

[whozum]

m and kg are base units, what are the base units of a Newton?

 

[dextercioby]

Yes,also "s" is the unit that enters "G"...Incidentally,in any system of units,SI-mKgs included...

Daniel.

 

[rindishy123]

i think i worked it out...

could anyone clarify if the correct base units are :

kg m² sˉ²

 

[Nylex]

i think i worked it out...

could anyone clarify if the correct base units are :

kg m² sˉ²

That's not right. What are the base units of a Newton, again?

 

[whozum]

No, you are missing something. Try this:

N x m^2 x kg^{-2}

If you can find the units of a Newton in base units, just plug it into the above expression and simplify to get the base units of G.

 

[rindishy123]

units of a Newton are m kg s-2

 

[dextercioby]

Okay.What about the fraction in the RHS of Newton's gravity law...?

Daniel.

 

[Nylex]

units of a Newton are m kg s-2

Yep, so how did you come up with your answer for the base units of G? .

 

[rindishy123]

i don't knoww! i mentioned i was **** at doing these things in my first post!

somebody please just tell me how to do it! this is in for tmoro!

 

[Nylex]

You have the base units of a Newton and the rest of your units for G are base units. As whozum said, just plug your base units for a Newton into your collection of units for G..

 

[whozum]

kg * m * s^{-2} * m^2 * kg^{-2}

Making it easier for you :)

 

[chroot]

It's just a fraction, rindishy:

N \cdot \frac{m^2}{kg^2} = \frac{kg \cdot m}{s^2} \cdot \frac{m^2}{kg^2} = ...

Cancel the redundant units, and you're done.

- Warren

 

[rindishy123]

ohh

so:

m3 kg s-2?

and how do you make those lovely italic expressions? :)

 

[dextercioby]

Not really.

m^{3}(Kg)^{-1}s^{-2}...

Using Latex.

Daniel.

 

[rindishy123]

ok I am off back to grade school