Circular Motion, only radius known

[zz227]

Homework Statement

A carnival ride has a large horizontal steel disc of radius 5.0 m from which cars are suspended by
6.0 m long chains. The disc is rotated about its axis so that the cars swing out and revolve in a
circular path. At its operating speed, the angle of the chains to the vertical is 20 degrees. Find the speed of the cars.

Homework Equations

a=mv^2/r

v=2*pi*r/T

The Attempt at a Solution

Ive started by treating it as a horizontal situation, and found the horizontal radius which equals 6*sin(20) + 5=7.05m. And now I am clueless, where do i go on from here?
Thanks.

 

[tiny-tim]

welcome to pf!

hi zz227! welcome to pf!

(have a pi: π and a degree: ° and try using the X² icon just above the Reply box )

draw a https://www.physicsforums.com/library.php?do=view_item&itemid=100" for one car …

there are only two forces, the tension and the weight, and they have to equal the mass times the https://www.physicsforums.com/library.php?do=view_item&itemid=27"

(the question tells you that it's a chain, ie floppy, so you know that the force will be along the chain)

 

[zz227]

thank you!

especially that last bit about the chain, never knew that!