# Uniform Circular Motion.

1. Jan 24, 2010

### Muneerah

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

The speed of the tip of the minute hand on a
town clock is 0.00182 m/s.
What is the speed of the tip of the second
hand of the same length?

What is the centripetal acceleration of the tip
of the second hand?

2. Relevant equations
ac=4pi2r/T2

3. The attempt at a solution
Ok to find the speed of the second, I multiplied by 60 and got .1092 m/s
for the acceleration I'm not given r, so I need to find r using this equation, V=2pi r/T
I was wondering what id T ? is it 60 seconds ? Thank you

Last edited: Jan 24, 2010
2. Jan 24, 2010

### ideasrule

V=2pi*r/T is just distance divided by time, so T has to be the time taken for the hand to make one revolution. Of course, that depends on which hand you're considering.

3. Jan 24, 2010

### kuruman

You can find r by using the angular velocity ω from v = ω r. What is ω for the second hand?

4. Jan 24, 2010

### Muneerah

so I found r which is 1.638m and I used 60s for T
I got .00728 for the acceleration and this isn't the right answer, please tell me what is it that I'm not doing right thanks.

5. Jan 24, 2010

### kuruman

If you don't show exactly how you got these numbers for the radius and for the acceleration, we cannot tell you what you are not doing right.

6. Jan 24, 2010

### Muneerah

I'm sorry, but it's ok I figured out what I was doing wrong.