# How do i convert ?

1. Jun 21, 2005

### gunblaze

I was reading a book on the theory of relativity yesterday and it said that by substituting the equation for momentum (p=mv) in to the formula E^2=m^2c^4+p^2c^2..
i will be able to get this E=gamma mc^2..
I was just wondering where they get the "gamma" from? can anyone pls tell me how they get that? Thx
sry, not really good at this.

2. Jun 21, 2005

### Pengwuino

gamme is equal to 1 over the square root of 1-((v^2)/(c^2))

3. Jun 21, 2005

### dextercioby

You need to be careful with the notation.

$$E^{2}=m^{2}c^{4}+p^{2}c^{2}$$

and $$p=\gamma m v$$.

Daniel.

4. Jun 21, 2005

### gunblaze

Isn't momentum=mass x velocity?

5. Jun 21, 2005

### Pengwuino

Not in relativistic physics. Its gamma * mass * velocity as v -> c

6. Jun 21, 2005

### gunblaze

erm.. can we put velocity, v, and speed of light, c, together?
eg: $$v^{2}c^{2}=c^{4}$$

Last edited: Jun 21, 2005
7. Jun 21, 2005

### gunblaze

but it sounds ridiculous rite? how can the velocity be equal to the speed of light?

8. Jun 21, 2005

### gunblaze

k.. guys, i get it alr..thx thx so much!

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