# Normal force in a compound pendulum (physical pundulum) system?

Consider a compound pendulum pivoted about a fixed horizontal axis, illustrated by the force diagram on the right:

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Okay, I can't figure out where the normal force on the pendlum should point (this force isn't indicated in the diagram).

On the one hand, I think it should point in the same direction as the tension force on the left-side diagram, in order to produce the rotation. But on the other hand, shouldn't the normal force point towards the pendulum rather than away from it? In any case, I know that normal face is perpendicuar to the contact surface, but how does "contact surface" fit into the context of this scenario?

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This seems to have been discussed at physics.stackexchange.com/questions/22248/… , but unfortunately I don't really understand the answers(comments) given there. –  Ryan Apr 28 '12 at 7:30