Nonuniform circular motion toy train

[Jennifer001]

Homework Statement

a toy train rolls around a horizontal 1.0m diameter track. the coeffifient of rolling friction is 0.10

a. what is the magnitude of the train's angular acceleration after it is released
b. how long does it take the train to stop if it's released with an angular speed of 30rpm.

Homework Equations

At=r(alpha)
A=v^2/r
Ff=uk*ma=uk*mg

The Attempt at a Solution

i know I am suppose to look for the angular acceleration but i don't know what the tangential acceleration is, is there a relationship between centripetal acceleration and tangential .. also i don't know how to include the friction coieff. into an equation..

PLEASE HELP IM SO LOST!



so i have

 

[tiny-tim]

a toy train rolls around a horizontal 1.0m diameter track. the coeffifient of rolling friction is 0.10

a. what is the magnitude of the train's angular acceleration after it is released
b. how long does it take the train to stop if it's released with an angular speed of 30rpm.
…
i know I am suppose to look for the angular acceleration but i don't know what the tangential acceleration is, is there a relationship between centripetal acceleration and tangential .. also i don't know how to include the friction coieff. into an equation..

Hi Jennifer001!

For a constant radius, the tangential acceleration is just dv/dt.

And you put the friction into Newton's second law to find the acceleration (or you could just use the work-energy theorem ), exactly as on a straight track.