# What techniques can be used to analyze a rod rotating about the edge of a table?

1. Apr 29, 2012

### worldbook

A uniform rod of length 4x is rotating about the edge O of the table. (The rod does not fall off the table.) The centre of mass G of the rod is distance x away from O. The rod is making an angle θ with the horizontal.

The only forces present are the weight W of the rod, the normal reaction N of the table on the rod and the frictional force S that prevents the rod from slipping off the table as it rotates. Let the Radial direction point from O to G, and the Transverse direction be anticlockwise.

I apologise for not including a diagram but it should be very quick to sketch.

Question: Would it be appropriate to approach this problem using Newton's 2nd Law and then resolving the equation into radial and transverse components? If so, am I suppposed to be considering the motion of a point on the rod, or the motion of the rod as a whole body?

In particular, are these eqns meaningful??

−m(xω^2)=S−Wsinθ
m(xα)=Wcosθ−N