Oct 20, 2014 · A unit vector is a vector in some direction whose magnitude is unity (1). If you have some other vector in the same direction, say R, which is not of unit length, then you can create a unit vector in the same direction by calculating $$\hat{r} = \frac{R}{|R|}$$ That is, divide the vector R by its own magnitude.

Oct 18, 2014 · 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

Sep 12, 2016 · Homework Statement F=(KQ1Q2)/r^2 • (r-hat) Why are we multiplying by r-hat? I understand that the equation helps us calculate the force between two charges. The book says that r=|r(bold)| I know that this is the magnitude sqrt(rx^2+ry^2+rz^2) rx= r with respect to the X position and so on...

Apr 11, 2014 · The unit vector r-hat is a geometric quantity, not a physical quantity. If one of the charges is at the origin and you are employing spherical coordinates, in spherical coordinates the radial unit vector r-hat points away from the origin. Chet

Jan 23, 2010 · del r^hat ~ D[phi] * del t * phi^hat Then... dr^hat/dt = D[phi] * phi^hat Sorry for the horrible formating but I don't know how to make this better. The Attempt at a Solution I have a few problems with this first why in the first equation is the phi needed? It would seem to me that del r^hat would just be equal to del phi^hat and the magnitude ...

Nov 11, 2012 · Okay, ##\hat r## is always supposed to point from the current (wire) segment ds towards the point P where you want to evaluate ##\vec B##. It's drawn backwards on segment 1. It should point towards P. It doesn't make any difference in the final answer because the contribution from segment 1 comes out zero either way.

Jan 25, 2022 · ## \nabla \cdot \left( \frac{1}{r^2} \hat{r} \right) = 4 \pi \delta^3 \left( r \right)## If so just use the divergence theorem and realize that the result is independent of size of the sphere. So if you shrink the sphere “infinitely” the integral needs to evaluate to the same thing, and same when you blow it up. Enter the Dirac-Delta.

Apr 7, 2013 · the r is a displacement vector in the first, and in the second it's a unit vector, but why is this so? Last edited: Apr 7, 2013 Physics news on Phys.org

Feb 25, 2013 · Following kreil, if you want to work in Cartesian coordinates, note that ##\large{\frac{\hat{r}}{r^2}=\frac{\vec{r}}{r^3}= \frac{x\hat{i}+y\hat{j}+z\hat{k}}{r^3}= \frac{x\hat{i}+y\hat{j}+z\hat{k}}{(x^2+y^2+z^2)^{3/2}}}## Or you can work in spherical coordinates and use the expression for the curl in spherical coordinates. See equation 89 here ...

Apr 12, 2013 · It looks like [itex]\hat{z}[/itex] is a unit vector in the axial direction, [itex]\hat{\phi}[/itex] is a unit vector in the circumferential direction, [itex]\hat{R}[/itex] is a unit vector pointing from the origin in an arbitrary spatial direction, and [itex]\theta[/itex] is the angle between the unit vector [itex]\hat{R}[/itex] and the z axis ...