In part b of step 1 the meter stick is balanced on the edge of the table. When the center of gravity is on top of the table there is no lever arm meaning that there will be no torque (note. The line in the middle of the meter stick is the center of gravity).
In part c of step 1, 100g (mass) is added to the end of the stick and when it is balanced there is no lever arm, but the center of gravity of the system is different than the center of gravity of the meter stick by itself.
Step 2 of solving for the mass of the meter stick was planning out what equations we needed and what measurements we needed to plug into these equations. My partner and I concluded that we would need to use the equation w=mg to convert mass to weight and vise versa. The other equation we needed to use was torque= force x lever arm. The measurements we got was the lever arm of the clockwise torque which was 22.7 meters and the counter clockwise lever arm which was 28 meters.
Step 3 we tried out our plan, and this is what it looked like:
First my partner converted 100g to .10 kg to put in the equation w=mg, this way we could find the force acting on the system in the clockwise direction. Since we already measured the lever arm in the clockwise direction we were able to find the torque of it using the equation torque= (.98)(22.7) and we got 22.25N. Then we knew that to find the lever arm of the counter clockwise direction we had to measure from the center of gravity of the system to the center of gravity of the meter stick which was 28cm. By using the equation counter clockwise torque = clockwise torque we were able to solve algebraically for the force which is equal to the mass of the stick. Our answer to the equation was that the stick weighed 81g, and when we weighed it on the scale we found that we were only .01g off our estimate.
I really like how you put all the pictures of your work on there so I could follow all the steps. I also like that the descriptions of the process and pictures are so good. The post was really good and I can not find anything that I could change even if I could.
ReplyDeleteJoey