Physics- really important please look and help?

Question

One end of a uniform 4.0-m long rod of weight
w is supported by a cable. The other end rests against the wall, where it is held by friction. The co-efficient of static friction between the walla nd the rod is .50. Determine the minimum distance,x,from point A at which an additional weight w(same as the weight of the rod) can be hung without causing the rod to slip at point A.

i cant find a picture but i hope that someone can truly help me on this problem..i have been working on this for a few days now and its really pissing me off T___T please help

thanks

Answer 1

Dear Becky,
Draw a Large Diagram of the situation, with the rod at an angle to the wall and a non-vertical cable (if you have not been given the value of the angles put them in as two different unknowns)

For Translational Equilibrium:
The sum of the forces is Zero.
Resolve the forces into Vertical and Horizontal Components.
Write down the two equations.

For Rotational Equilibrium:
The torque or moments about any point on the rod must sum to zero. Take cw as positive torques and acw as negative:
Write down the equation for this.

Now get the equation in terms of x=
You should then be able to identify a maximum or minimum value of x that fits in with the physical situation.

If this does not help you: Repost the question with any missing parameters.
I hope this helps. Good luck.