Einstein's famous formula states that E = mc squared. Rewrite the formula with c as the subject.

Question

Einstein's famous formula states that E = mc squared. Rewrite the formula with c as the subject.

please help and show all your working out! 

Thank you very much!! 

Answer 1

Hello, Kath

 

If E = mc²

 

then

 

c² - E/m

 

and

 

c = √(E/m) or (E/m)^½

 

 

Answer 2

Hi again Kath;

According to my college physics professor, E=mc² is an over-simplification of the mathematical formula.  The way E=mc² has been taught in the grammar schools drove him crazy.

 

Unfortunately, I no longer have my college notes.  I researched this on the internet.  In its original form, the formula is ...

E²=[(m²)(c⁴)]+[(p²)(c²)]

 

E=energy of the particle

m=rest mass

p=momentum, also represented as mass multiplied by velocity, (mass)(velocity), p=mv.

c=speed of light, 299,792,458 meters per second.

If the mass is not moving, then p, momentum, is zero, because velocity (speed and direction of motion) is zero...

E²=[(m²)(c⁴)]+[(0²)(c²)]

Then this is...

E²=m²c⁴

The square root of both sides is...

E=mc²

As William explained, this can also be represented as...

c=√(E/m) or c=(E/m)½

 

As to the original equation, I do not know of any way of isolating c as the subject.

 

I know this does not answer your question.  I just want to ask of you not to drive your college professors crazy.