# Find the radius of a particle's circular path

1. Jun 9, 2017

### David Williams

1. The problem statement, all variables and given/known data
A particle moves along a circular path over a horizontal xy plane at a constant speed. At time t1= 3.00s, its acceleration vector is given by (3i-5j) m/s^2. At time t2=7.00 s, its acceleration is given by (-3i+5j) m/s^2.
Find the radius of the particle's circular path.

2. Relevant equations
centripetal acceleration = v^2/r

3. The attempt at a solution
Stumbling around for about an hour with no clue what to do... left me with nothing to show for.

2. Jun 9, 2017

### BvU

Hello David,

Doesn't count as an attempt at solution; according to the PF rules we're not allowed to assist in such a case.

But for a first post I'll stick out my neck : You have two acceleration vectors; notice anything particular about them ? Could that help you towards another expression involving $v$ and $r$ ?