Solving a Circular Motion Problem: Is Something Wrong?

[RoyalewithCh33s3]

Hello again, tonite I am working on more homework and I am stuck on a problem involving circular motion. Here's the question:

Q: A 24 kg child takes a ride on a fast Ferris wheel that rotates 4.5 times each minute and has a diameter of 19 m. (a) What is the centripetal acceleration of the child?

Ok so I would start out by turning 4.5 rev/min into rad/sec:

4.5 rev/min x $$\frac {1 min}{60 sec}$$ x $$\frac{2 \pi rad}{1 rev}$$ = $$.3\pi \frac{rad}{sec}$$

Then R = 9.5m

$$a_c$$=$$\omega^2$$R

$$a_c$$=$$9.5(.3\pi)^2$$

$$a_c$$ ended up being 8.44 m/s for me.

Is there something I'm doing wrong?

 

[skeeter]

4.5 rev/min = 3pi/20 rad/sec