# Vertical circle motion

1. Sep 29, 2011

### ethex

1. The problem statement, all variables and given/known data
A ball of mass m is suspended from a rope of length R. The ball is set into freely swinging circular motion a vertical plane. The centripetal acceleration of the ball at the top of the circle is 13g. What is the centripetal acceleration of the ball at the bottom of the circle.

2. Relevant equations

3. The attempt at a solution

At the top,

T + mg = mv^2/R

At the bottom, T - mg = mv^2/R

My question is does Ttop and Tbtm the same?

Hint for this question?

2. Sep 29, 2011

### grzz

Using conservation of energy principle helps you get v(top) in terms of v(bottom) and you may deduce whether the tensions are equal.

3. Sep 29, 2011

### ethex

Ui + Ki = Uf + Kf

0 + 0.5mVbtm^2 = 2mgR + 0.5mVtop^2

Right?

4. Sep 29, 2011

### grzz

Yes. Continue.

5. Sep 29, 2011

### ethex

I got 17g!

6. Sep 29, 2011

### grzz

Now you know what the answer to your question.

7. Sep 29, 2011

### ethex

Yes! thank you.!

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