# Centripetal force/acc problem

1. Feb 26, 2007

### iamtrojan3

1. The problem statement, all variables and given/known data
What angular velocity would cause a centripetal acceleration of 3 g's if the radius were 2.5 m?

i have a test 2moro on this stuff... yea i need to know =D thx

2. Relevant equations

i guess m(v^2)/r or mW^2r

3. The attempt at a solution

no idea. srry

2. Feb 26, 2007

### Edgardo

What is the W? And what do you calculate with mW^2r?

3. Feb 26, 2007

### iamtrojan3

W is rotational velocity.. sryy for not making that clear.
W^2R= Centripetal Acceleration
I just plugged numbers in 29.4= W^2(2.5) and i got 3.4radian/sec for W.
this looks 2 easy... if someoen could verify please =D

4. Feb 26, 2007

### Edgardo

Yes, very good, your answer is correct. But you should also write down the units, for example acceleration is in m/s^2 and radius in m. This allows you to check whether your result is correct.

For example if you calculated W as something with 1/s^2, you know you made a mistake because the unit must be 1/s (or radian/sec).

Last edited: Feb 26, 2007
5. Feb 26, 2007

### iamtrojan3

thanks tons edgardo!