0
votes
1answer
343 views

CGS Units to SI Units

This may be a stupid question but I am having trouble getting the same result in CGS units as I would if I used SI units for a unitless calculation. I have to calculate $E_c=\frac{m_e c\, ...
5
votes
3answers
298 views

What is a “measure equation” as mentioned by this TeX Users Group guide?

In this TeX Users Group (TUG) document, Typesetting mathematics for science and technology according to ISO 31/XI by Claudio Beccari, the author makes various typesetting recommendations including: ...
4
votes
1answer
246 views

Avogadro's number

Could I get an explanation of Avogadro's number and how it relates to determining the mass of a substance? My chemistry textbook only serves to confuse me and the Wikipedia article is aimed towards a ...
2
votes
2answers
636 views

Fundamental units

Is it right that all units in physics can be defined in terms of only mass, length and time? Why is it so? Is there some principle that explains it or is it just observational fact?
-1
votes
3answers
315 views

Help getting the distance an object has moved

What is a distance an object went through at the speed of 14hm/min for 6 hours? I am having problems with conversions. First, I tried passing 14hm/min to m/s. I did it alright. But now I am unsure. ...
0
votes
2answers
1k views

Why does $E=mc^2$ give results in Joules?

Why does $E=mc^2$ give results in Joules ? Why didn't Einstein need to create a separate unit and how come using two standard units (speed of light in km.s and mass in grams) give another result in ...
8
votes
3answers
2k views

Coulomb force in SI and cgs

Coulomb force in SI is $ F = \frac{Q1*Q2}{4\pi\varepsilon R^{2}} $ while in CGS $ F = \frac{Q1*Q2}{R^{2}} $ why is it? I mean doesn't it any make difference in dimension? since $ \varepsilon $ ...