# What is a transformation law?

1. Jun 15, 2014

### ggolu2

I really don't understand what it is and what is the use of constant, like in this equation of transformation.
x=k(x' + vt).
The equation can also be good if it is just like this,
x=x' + vt

Thank you.

2. Jun 15, 2014

So you are saying the $$F=\frac{m_1m_2}{r^2}$$?

That is certainly not true.
Do you believe that $F=x$?(Hookes law)
Yes this is valid for a elastic constant of 1 but not valid for any other constant.

3. Jun 15, 2014

### ggolu2

No this is about theory of special relativity. It uses transformation law to derive the equations of Lorentz transformation. And my question is about the use of the constant, I mean how they thought that there must be a constant such that this equation holds good at high speeds.

4. Jun 15, 2014

### Hepic

Are you sure there is constant "k"?
Also if there is,then what is the value of "k" ?

5. Jun 15, 2014

### Staff: Mentor

The Lorentz transformation for x is
$$x^\prime = \frac{x - vt}{\sqrt{1 - v^2/c^2}}$$
You should be able to read off the value of k from that equation. (We usually call it $\gamma$.)

Last edited: Jun 15, 2014