Free Fall Lab- determination of g
introduction:
Generally, object on the earth have gravity, and a free falling object will accelerate at 9.8m/s2downward. We learn that knowledge in high school and now we try to find by ourselves.
setting:
1. put the long paper in the free falling apparatus
2. set the sparker box on the very top and turn on the
electromagnet make it hold.
3. let it start sparking at 60 hz and turn off the electromagnet
4. sparker box will leave dots on the paper while it falling down
5. measure the distance
thesis:
Our purpose is to find the accelerate if it close to the gravity accelerate 9.8m/s2.
We use the free falling apparatus to collect the dot which the sparker box leave when it falling down. Then we can use the distance between every 1/60 s which is ∆X=Xn -Xn-1 to find mid-interval speed.
∆X/(1/60)=V(mid-interval speed) and ∆V= Vn -Vn-1 ,∆V/(1/60)= accelerate then compare with accelerate of gravity.
date and calculation:
paper with dots . This is our date from. We measure the distance from 0 cm mark, then type it in the Microsoft Excel.
here is the excel date we did in class
we use excel to make this graph. it shows that slope =970.02(cm/s2)
d/dt v(t)=a(t)=970.02(cm/s2) =9.7002(m/s2)
This is the date from other group. there are 9 groups, ours is 4
Conclusion:
Except and experiment are different our experiment is that each result have different accelerate.
According to the standard deviation of the mean theory 68% of us get 9.57+or-0.18 in the standard deviation from the mean value.
our group get 9.696 we can find our error is (9.696-9.8)/9.8=-1%
setting:
 |
| free fall apparatus from(http://web.alfredstate.edu/quagliato/lab/lab.htm) |
2. set the sparker box on the very top and turn on the
electromagnet make it hold.
3. let it start sparking at 60 hz and turn off the electromagnet
4. sparker box will leave dots on the paper while it falling down
5. measure the distance
thesis:
Our purpose is to find the accelerate if it close to the gravity accelerate 9.8m/s2.
We use the free falling apparatus to collect the dot which the sparker box leave when it falling down. Then we can use the distance between every 1/60 s which is ∆X=Xn -Xn-1 to find mid-interval speed.
∆X/(1/60)=V(mid-interval speed) and ∆V= Vn -Vn-1 ,∆V/(1/60)= accelerate then compare with accelerate of gravity.
date and calculation:
paper with dots . This is our date from. We measure the distance from 0 cm mark, then type it in the Microsoft Excel.
here is the excel date we did in class
using the ∆V to find the average accelerate and average it can get a=969.23(cm/s2) =9.69239(m/s2) which is really close to g=9.8(m/s2) but the air resistance affect the lab result.
we use excel to make this graph. it shows that slope =970.02(cm/s2)
d/dt v(t)=a(t)=970.02(cm/s2) =9.7002(m/s2)
This is the date from other group. there are 9 groups, ours is 4
Except and experiment are different our experiment is that each result have different accelerate.
According to the standard deviation of the mean theory 68% of us get 9.57+or-0.18 in the standard deviation from the mean value.
our group get 9.696 we can find our error is (9.696-9.8)/9.8=-1%
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