# Tangential & normal vs radial & transverse

by Lifprasir
 P: 13 What is the difference between "tangential and normal components" and "radial and transverse components" ? I mean in both cases, the two components are perpendicular to each other and one of the components causes the particle to rotated around, the other one gives it a speed to rotate with. Is it just a matter of different coordinate system, where the tangential + normal are written with respect to cartersian while the radial and transverse is written according to r and theta?.. but other than that, the components do serve the same function right?
 Sci Advisor PF Gold P: 1,847 There is no difference for circular motion but other types of motion are possible. "Tangential and normal" are relative to the direction of travel. "Transverse and radial" are usually relative to the origin of the coordinate system, or the centre of some circular symmetry.
HW Helper
P: 6,679
 Quote by Lifprasir What is the difference between "tangential and normal components" and "radial and transverse components" ? I mean in both cases, the two components are perpendicular to each other and one of the components causes the particle to rotated around, the other one gives it a speed to rotate with. Is it just a matter of different coordinate system, where the tangential + normal are written with respect to cartersian while the radial and transverse is written according to r and theta?.. but other than that, the components do serve the same function right?
If you are using polar coordinates (or spherical or cylindrical coordinates) rather than cartesian coordinates to describe a vector quantity, the basis vectors are not fixed.

The basis vectors for polar coordinates are $\hat r$ and a unit vector in the plane of the vector but perpendicular to $\hat r$ (call it $\hat l$). $\hat r$ is the radial basis vector and $\hat l$ is the transverse basis vector. It may be convenient to analyse rotational motion using polar coordinates.

If you are describing rotational motion of a body you may wish to describe a component of motion that is in the direction of the body's motion and a component that is perpendicular to it. Those components may or may not have the same directions as the radial and transverse basis vectors (which depend not on the direction of motion but on the location of the origin). The normal and tangential components (eg. of velocity or acceleration) will have the same directions as radial and transverse basis vectors if the body's motion is circular about the origin.

AM

 P: 1,115 Tangential & normal vs radial & transverse A quick Google and Wikipedia search reveals people equating tangential to transverse, and radial to normal, without caveats. Words are ambiguous. How are these words defined in your particular textbook? If your lecturer is using one of these words, ask him *exactly* what he means by it. If you are just pulling them out of thin air then I suggest you find something better to do.

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