# Taking square?

1. Dec 20, 2008

### Naimbora

Taking square???

Why do we need to take square? What does it mean? For instance, calculating energy, why do we need to take square of the velocity or taking square of time in some other formulas?

In general, what is the mathematical meaning of taking square?

2. Dec 20, 2008

### NoMoreExams

Re: Taking square???

Think dimension? If I told you that area of your room was 50 feet what would that mean to you?

3. Dec 20, 2008

### Hootenanny

Staff Emeritus
Re: Taking square???

The mathematical meaning of taking the square (of a number) is simply multiplying a number by itself, raising it to the second power etc. In the case of a vector this means taking the scalar product of the vector with itself.

The physical interpretation on the other hand is something completely different.

4. Dec 20, 2008

### Naimbora

Re: Taking square???

Ok, i think that i asked the question in a wrong way.. I did mean the physical interpretation of "taking square" as Hootenanny said above.

5. Dec 20, 2008

### Hootenanny

Staff Emeritus
Re: Taking square???

There is nothing particularly special about a squared quantity, the fact the some quantity is squared simply arises as a matter of course from their derivations.

Of course, some people would say that its strange that so many physical laws contain powers of two; but conversely there are many that don't. Personally, I don't feel that there is any special physical interpretation to physical laws or equations containing terms to the second power.

Of course, one can draw conclusions from certainly formulae. For example, you cite kinetic energy; from this equation one can conclude firstly that kinetic energy is a scalar quantity and secondly that kinetic energy is always positive.

6. Dec 20, 2008

### HallsofIvy

Staff Emeritus
Re: Taking square???

Thank you, Hootenanny. I seem to get barked at everytime I make the point that mathematical concepts do NOT have "physical meaning".