Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Paul Young on 01/10/2011 10:30:03

Title: Why c squared?
Post by: Paul Young on 01/10/2011 10:30:03

Paul Young  asked the Naked Scientists:
   
Chris

Basically, what is the relevance of "c squared" in Einstein's famous equation E=mc^2?

ie if light is the fastest speed then why is it squared in the equation?

I think relevant now given the latest revelations that maybe some particles are faster than the speed of light

All the best

Paul Young

What do you think?

Title: Why c squared?
Post by: yor_on on 01/10/2011 14:19:01

It is a indication of the 'energy' intrinsic to matter, as I see it. And so it becomes 'c' squared.

Title: Why c squared?
Post by: Soul Surfer on 01/10/2011 23:50:01

The c squared term basically comes from the kinetic energy of an object in motion that is for a body of mass m moving at a velocity of v the kinetic energy increases as v squared now to sort out the squared term.

The measure of energy consists of two parts, an applied force and a distance moved.

So when adding energy to a body by applying a force for a particular time period we need to consider how big the force is and how far the mass would move

The most fundamental equation of motion is that the acceleration a mass is proportional  to the force applied 

Next we have to find out the distance traveled in a time period as a result of the acceleration that the force has created

for a uniform acceleration from stationary  the velocity is the aceleration times the time over which it has operated

and the distance covered is the velocity times the time period too

so for a given time period  the distance travelled is a constant (1/2)  x velocity x velocity 

That is, vlocity comes into it twice to make it velocity squared