Angular velocity- A toy train rolls around a horizontal track

[Ediscoverlyf]

Homework Statement

A toy train rolls around a horizontal 2.0m diameter track. The coefficient of rolling friction is 0.15. How long does it take the train to stop if it's released with an angular speed of 30rpm?

Relevant Equations

1 revolution = 2pi radians
final angular velocity = initial angular velocity + angular acceleration (time)
F = ma
+other circular motion equations

30 rmp (2 pi) = 60 radians/minute = 1 revolution/sec
0 = 1revolution/s + angular acceleration (t)
The only force acting on the toy train at this point is the force of friction. How do I use the coefficient of friction to find angular acceleration?

Thank you so much in advance, I literally have no clue how to go about this problem.