# What is R hat in physics

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1. Oct 18, 2014

### Mary O'Donovzn

Hi

I am struggling big time with Physics and vectors and I keep coming across r hat (^) like what is it exactly and how do you calculate it?

2. Oct 18, 2014

### A.T.

3. Oct 18, 2014

### Vagn

The hat on a vector usually means it is a unit vector, i.e. a vector of length 1 in the direction of r.

4. Oct 18, 2014

### Staff: Mentor

You'll need to provide more context to get a helpful answer. Often, $\hat r$ is a unit vector in the radial direction.

5. Oct 18, 2014

### Staff: Mentor

Context... we need some context... Without that all we can say for sure is that it's an r with hat over it.

However, there is a very good chance that it is a unit vector in some direction of interest, and what that direction is will depend on the specific problem that's being discussed.

6. Oct 18, 2014

### Mary O'Donovzn

okay so in the exam paper it says that "r hat is the unit vector along the line of action between the charges. the question is regarding coloumbs law"

so I'm given the magnitude of the vectors and the corordinates of three charges and I need r hat to solve it

7. Oct 18, 2014

### Staff: Mentor

You will get much better results for this sort of question if you post in the homework section. Please use the template that appears when you start a thread there - it helps you organize your thoughts, helps the homework helpers (who are, BTW, underpaid volunteers) know where to start, and it's required by the rules in any case.

I'm closing this thread now - further discussion belongs in the homework sections.

8. Oct 19, 2014

### Staff: Mentor

Where "underpaid" means "unpaid", unless you count things like psychological satisfaction and Internet glory. :D