# Angular acceleration of a pendulum on an accelerating train

1. Sep 24, 2008

### Harmony

If I hang a pendulum on the ceiling of an accelerating train (with an initial angular displacement), how would the angular acceleration be affected?

My intuition told me that the angular acceleration of the pendulum should be affected by the acceleration of the train. But...whether the train accelerate or not, the force acting on the tangential direction of the pendulum is still the mass of the pendulum right? So it seems tat the angular acceleration of the pendulum will be affected by length and gravitational acceleration alone, and not the acceleration of the train?