# Kinematics of a particle - Curvilinear motion of cylindrical components

1. May 5, 2010

### steven86

hi guys,

I have a question about the names of parts in the formula for accelerating a partical using polar coordinates.

The formula for acceleration is:

a=arur+a$$\theta$$u$$\theta$$

where:
ar=r"-r$$\theta$$'2
a$$\theta$$=r$$\theta$$"+2r'$$\theta$$'

In these two equations
r" occurs due to exdending or shortening the arm
r$$\theta$$'2 occurs due to the centrifugal force
r$$\theta$$" occurs due to the angular acceleration
but how is this term called? : 2r'$$\theta$$'