What is the Mass of Meter Stick in Sketch?

[jammhawk]

Homework Statement

What is the mass of the meter stick, which is shown in the sketch below while it is balanced?

http://img252.imageshack.us/img252/9819/problemeo4.jpg
a 160 grams b 120 grams c 80 grams d 200 grams e none of the above

Homework Equations

The Attempt at a Solution

I am completely CONFUSED! Our professor never discussed finding the mass of the lever.

 

[thepanda]

The meter, you can think of like a mass that adds torque to the system. Consider the each side of the meterstick as a mass concentrated at that center of gravity for the side. Then you can solve for the sum of the torques = 0.

 

[christensen]

To reiterate what thepanda said, think of the leaver as mass less, and simply assume there is a mass of "x" weight hanging from the 50cm mark of the meter stick (20cm to the right of the fulcrum). Simply solve for "x".

*It is placed here because it is the object's center of mass

 

[jammhawk]

Okay I know I am going to sound completely stupid, but I am still getting really confused. I have a political science degree and working on a history degree. I am in the lowest level physics and I am still getting really confused.

Sorry.

 

[jammhawk]

so does X = 120 grams?

 

[christensen]

that is the correct answer.