# Homework Help: HELP Statics problem

1. Nov 25, 2008

### Kudo Shinichi

HELP!!!Statics problem

1. The problem statement, all variables and given/known data
A thin rod AB of length L=0.5m and mass m=1.0kg makes an angle of theta=60 degree with the horizontal. It is held in position by a horizontal light string attached at A as shown. A mass M is suspended from A by a second string. If the coefficient of friction between the rod and the ground at the point of contact B is mu(s)=0.50, what is the largest mass M that can be suspended such that the rod does not slip.
Diagram:
http://tinypic.com/view.php?pic=121slk5&s=4

3. The attempt at a solution
we need to use the equilibrium conditions to solve the problem. therefore, Sigma(Fx)=0,Sigma(Fy)=0 and Sigma(torque)=0
Sigma(Fy)=FN-mg=0
therefore, normal force=mg=1*9.8=9.8N
Sigma(Fx)=frictional force-exerted force=0
this is what I know for solving the problem so far...I know that I have to somehow relate the rod with the hanging mass.
Ignoring the ways I attempted above, I think that i can get the mass by
M=1.0kg*cos(30o)
but I think it is not the correct answer.
Can anyone help me with it? thank you very much.

Last edited: Nov 25, 2008
2. Nov 25, 2008

### LogicalTime

Re: HELP!!!Statics problem

hmm, the forum seems to have some issues with generating certain latex input, I can't read half your post,

I wonder if there is a thread on latex forum input tips

3. Nov 25, 2008

### Kudo Shinichi

Re: HELP!!!Statics problem

I have change the format, I think that you will be able to view it without any problem.

4. Nov 26, 2008

### LogicalTime

Re: HELP!!!Statics problem

first pretend there is no friction and that the thing is just anchored. put down two equations one for forces in the x direction and for forces in the y direction. I called the tension in the string T1 and tension in the rod T2