# Homework Help: Tangential, Radial Components of Acceleration Quick Question

1. Feb 14, 2010

### jumbogala

1. The problem statement, all variables and given/known data
Are you supposed to write directions for the tangential and radial components of acceleration?

2. Relevant equations

3. The attempt at a solution
Because they are components, I'd say no... isn't a component usually written without a vector sign, and therefore no direction?

The thing is, components DO have direction. Radial acceleration is towards the center of the circle, while tangential is tangent to the circle. Couldn't these values also be positive or negative? If I define a unit vector $$\hat{r}$$ that points OUTWARDS from the center of circle, wouldn't my radial acceleration be negative?

2. Feb 14, 2010

### PhanthomJay

The tangential and radial components of an acceleration must have a direction assigned to them, just as components of forces for example must have a direction. Often the direction is indicated as plus or minus, or in or out, or up or down, etc.

3. Feb 14, 2010

### ideasrule

Who cares? As long as you show your work clearly, it doesn't matter. Just make sure you don't include a vector sign on the acceleration if you don't include a vector sign on its value (e.g. don't write a-arrow=v^2/r; write either a=v^2/r or a-arrow=v^2/r r-hat).