# Rotational Dynamics - Algebra Based

1. Jul 7, 2009

### physicistj

I have been trying to get ready for my final and rotational dynamics seems to be very difficult for me. I have read the book and feel like I am just not comprehending what the concepts are. Here is a problem I am stuck on.

A uniform board is leaning against a smooth vertical wall. The board is at an angle theta above the horizontal ground. The coefficient of static friction between the ground and the lower end of the board is 0.650. Find the smallest value for the angle theta, such that the lower end of the board does not slide along the ground.

Again, this is algebra based physics, and if someone does have a solution, can you please explain maybe the concept of rotational dynamics as well?

Thank you so much,
Lost

2. Jul 7, 2009

### turin

Firstly, you should understand that this problem is a statics problem, not a dynamics problem. For your purposes, then, acceleration vanishes (i.e. in Newton's second law). For the translational version, all you need to determine are the forces that act on the object (the board). However, for the rotational part, you need to know these same forces, and where they are applied to the body.

BTW, you must show us an attempted solution before we help.