You've taken your neighbor's young child to the carnival to ride the rides. She wants to ride The Rocket. Eight rocket-shaped cars hang by chains from the outside edge of a large steel disk. A vertical axle through the center of the ride turns the disk, causing the cars to revolve in a circle. You've just finished taking physics, so you decide to figure out the speed of the cars while you wait. You estimate that the disk is 6m in diameter and the chains are 6 m long. The ride takes 10s to reach full speed, then the cars swing out until the chains are 25 degrees from vertical.What is the car's speed?

3 answers

http://answers.yahoo.com/question/index?qid=20090308072337AA3lVRt
I tried that one but i'm not getting the right answer
diameter of the disk (d) = 6 m
length of the chains (L) = 6 m
time (t) = 10 s
angler formed (θ) = 25 degrees
total radius = (6/2) + ( 6 × sin 25 )
centripetal force (F) = mv^2/r
m x g x tan 25 = mv^2/r
g x tan25 = v^2/r
9.8 x tan 25 = v^2/5.5
v^{2} = 5.5 x 9.8 x tan 25 = 25.13
v = 5.01 m/s