# Find the radius of a particle's circular path

#### David Williams

1. Homework Statement
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. Homework 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.

Related Introductory Physics Homework Help News on Phys.org

#### BvU

Homework Helper
Hello David,

no clue what to do
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 $r$ ?

"Find the radius of a particle's circular path"

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving