Solve the all parts of following question:
Question: A toy train rolls around a horizontal 1.2-m-diameter track. The coefficient of rolling friction is 0.10.
Part A: What is the magnitude of the train's angular acceleration after it is released?
Part B: How long does it take the train to stop if it's released with an angular speed of 30rpm?
I need help to find the magnitude of the train's angular acceleration after it is released.