# Homework Help: Tension physics help

1. Jun 8, 2013

### katiegerster

1. The problem statement, all variables and given/known data

3. A plank of length L=1.800 m and mass M=7.00 kg is suspended horizontally by a thin cable at one end and to a pivot on a wall at the other end.The cable is attached at a height H=1.50 m above the pivot and the plank's CM is located a distance d=0.700 m from the pivot. Calculate the tension in the cable.

2. Relevant equations

T=mg
T=ma
T-ma=mg

3. The attempt at a solution

how do you solve for tension with the values given? they don't fit into any equations I have..
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jun 8, 2013

### voko

You need the equations for static equilibrium.

3. Jun 8, 2013

### katiegerster

what are those?

4. Jun 8, 2013

### voko

I do not think that you were given the problem without being taught about static equilibrium first. You may want to review your course materials and whatever textbooks assigned. This might be helpful somewhat: http://en.wikipedia.org/wiki/Mechanical_equilibrium

5. Jun 8, 2013

### mrcotton

Did you learn the principle of moments on your course?