Torque Equilibrium: Solving f=ma and T=rf

[rphung]

Homework Statement

Homework Equations

f=ma
T=rf

The Attempt at a Solution

i can't really visualize the model of the bar. But isn't the force needed to balance out the bar, just the sum of the weight of the bar, and the two masses on the left and right?

 

[Dick]

Sure it is. I assume next they will ask where that force must be applied so the bar is in rotational equilibrium as well. Then you need the torques.

 

[rphung]

yeah that is the next question. Do you have any pointers on this one? How does the mass of the bar contribute to the torque?

 

[Dick]

yeah that is the next question. Do you have any pointers on this one? How does the mass of the bar contribute to the torque?

Only forces contribute to the torque, not masses. Just pick an origin, add them up, set to zero and solve for the unknown position.