# What is the meaning of the sum of tan A and rad A?

1. Sep 27, 2009

### Shing

Today I was doing a homework that asked me to calculate the sum of some particular tangential acceleration and radial acceleration in a circular motion.

We all know clearly about the concepts independently, but I wonder what the physical meaning the sum of the two accelerations is? Or it is just a some kinda tool like math?

2. Sep 27, 2009

### Staff: Mentor

Presumably they want the vector sum of those two orthogonal components, which gives you the total acceleration of the body.

3. Sep 28, 2009

### Shing

so what is the physical meaning of the total acceleration?
Is it something produced by the two accelerations' definitions?

4. Sep 28, 2009

### diazona

It's the rate of change of velocity. Just the plain old regular acceleration that you've hopefully learned about before...

5. Sep 28, 2009

### Gear300

Basically, any particle undergoing a curved path has an acceleration (which is what allows it to curve) - the components of the acceleration could have been taken in any direction not orthogonal to the acceleration, but since we have a conceptual basis of perpendicular to the path and tangent to the path, its easier to give the components in terms of those directions.

Last edited: Sep 28, 2009