Part 1:
During this lab, the first thing that we did was test at which point the meter stick would not balance on the edge of the table. When the meter stick did not balance, its center of gravity was off the edge, and therefore it had a counter clockwise torque. Then, we tested at which point the meter stick would balance, and we discovered that when the center of gravity was in line with the pivot point, the stick stayed balanced, and therefore had no torque. The first example had a torque because it had both a force (gravity) and a lever arm (distance pivot point is away from the center of gravity where it starts to fall). The second example did not have torque because even though there was the force of gravity acting on it, it however didn't have a lever arm and therefore had no torque.
Part 2:
Next we added a 100 gram mass to the edge of the meter stick and watched how the balance point changed. To find the torque of the meter stick, we used the equation:
Torque = Force x Lever Arm
We discovered that the meter stick balanced at 29.5 cm away from the pivot point. With this information we plugged in numbers to the equation. For force, we used gravity, 9.8, and for lever arm, we used the distance away fro the pivot point which was 29.5. The next thing we did was plan how we were going to find the mass of the meter stick. My group and I decided that the equation that we needed was the Angular Momentum equation.
For this equation, we needed to know the lever arm both before and after. To find this we used our knowledge that the center of gravity was acting on the 50 cm point. And since the lever arm for before (when it is balanced) was 29.5 cm, we subtracted 29.5 from 50 and got 20.5 to find the lever arm for after (distance from pivot point to center of gravity. We knew this because no matter how much mass we put on the stick, its mass by itself will remain the same. Now, since we already knew the force for before (9.8=gravity) we were now just solving for the force after.
Part 3:
Now, all that was left to do was plug in numbers and solve for the mass of the stick. Using the equation:
Counterclockwise torque = Clockwise toque
. . .
Lever Arm x Force = Lever Arm x Force
before after
29.5 x .98 = 20.5x
28.91 = 20.5x
20.5 20.5
x = 1.41 N
Now we know the weight of the stick, we have to convert Newtons to kilograms. To do this we had to use the equation:
w = mg
Plugging in the numbers, we got,
1.41 = 9.8m
9.8 9.8
There for the mass of the meter stick = .143 kg
During this lab, the first thing that we did was test at which point the meter stick would not balance on the edge of the table. When the meter stick did not balance, its center of gravity was off the edge, and therefore it had a counter clockwise torque. Then, we tested at which point the meter stick would balance, and we discovered that when the center of gravity was in line with the pivot point, the stick stayed balanced, and therefore had no torque. The first example had a torque because it had both a force (gravity) and a lever arm (distance pivot point is away from the center of gravity where it starts to fall). The second example did not have torque because even though there was the force of gravity acting on it, it however didn't have a lever arm and therefore had no torque.
Part 2:
Next we added a 100 gram mass to the edge of the meter stick and watched how the balance point changed. To find the torque of the meter stick, we used the equation:
Torque = Force x Lever Arm
We discovered that the meter stick balanced at 29.5 cm away from the pivot point. With this information we plugged in numbers to the equation. For force, we used gravity, 9.8, and for lever arm, we used the distance away fro the pivot point which was 29.5. The next thing we did was plan how we were going to find the mass of the meter stick. My group and I decided that the equation that we needed was the Angular Momentum equation.
For this equation, we needed to know the lever arm both before and after. To find this we used our knowledge that the center of gravity was acting on the 50 cm point. And since the lever arm for before (when it is balanced) was 29.5 cm, we subtracted 29.5 from 50 and got 20.5 to find the lever arm for after (distance from pivot point to center of gravity. We knew this because no matter how much mass we put on the stick, its mass by itself will remain the same. Now, since we already knew the force for before (9.8=gravity) we were now just solving for the force after.
Part 3:
Now, all that was left to do was plug in numbers and solve for the mass of the stick. Using the equation:
Counterclockwise torque = Clockwise toque
. . .
Lever Arm x Force = Lever Arm x Force
before after
29.5 x .98 = 20.5x
28.91 = 20.5x
20.5 20.5
x = 1.41 N
Now we know the weight of the stick, we have to convert Newtons to kilograms. To do this we had to use the equation:
w = mg
Plugging in the numbers, we got,
1.41 = 9.8m
9.8 9.8
There for the mass of the meter stick = .143 kg
This blog post looks great!! What really worked well for me understanding the lab were the equations- which you did a good job mentioning it. What I saw very helpful that you did was dividing the blog into three parts. It made it really easy to follow what you said. The only piece of advice I would give to you for next time is to maybe add pictures. I know it would've been hard to add pictures for this one, what with the complicated diagrams- but maybe next time add some pictures to emphasize your point. Other than that, great post!
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