# Kinematic particle

1. Sep 15, 2016

### dirk_mec1

1. The problem statement, all variables and given/known data

2. Relevant equations
Formulas for a_r and a_theta.

3. The attempt at a solution
I got the second derative of r but I think the fluxie v is a mistake. I am sure that
$\dot{v} =a\$, right?

2. Sep 15, 2016

### haruspex

The statement of the question is rather unclear. If v is the velocity, dv/dt is a vector, but it doesn't ask about the direction. Maybe it means to ask for $|\dot{\vec v}|$.
The given acceleration appears to be the radial component only, so is not the same as either $|\dot{\vec v}|$ (the total acceleration) or $\ddot r$.

3. Sep 16, 2016

### dirk_mec1

Yes but the radial acceleration is the total acceleration $a =a _r$ so it should be the same right?