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Investigating circular motion

  • Thread starter Seneka
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Problem Statement
What are the systematic and random errors associated with this experiment? How can I reduce the effects of these? How can I reduce percentage uncertainty?
Relevant Equations
-
Random error would be to do with not swinging the bung in a perfect circle so when I try to measure velocity, that would vary. Measurement of radius.

How would I decrease percentage uncertainty?
Use a smaller mass so that I get a larger radius so I can measure a longer length.
 

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Seriously? You're going to post the image sideways so we have to get a kink in our necks to look at it? Not a good idea.
 
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Seriously? You're going to post the image sideways so we have to get a kink in our necks to look at it? Not a good idea.
I've adjusted it now.
 
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Great. Now if you could just make it readable ...
 
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Great. Now if you could just make it readable ...
There's not much to read. The diagram says it all. The procedure just says to swing the bung in a horizontal circle until the suspended weight remains stationary as this is when the weight is equal to the centripetal force. The paperclip acts as a marker to make this movement clear.

It's investigating the centripetal force required for different masses, radii and velocity. So the measurements taken will be the radii and velocity.
 

ZapperZ

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Problem Statement: What are the systematic and random errors associated with this experiment? How can I reduce the effects of these? How can I reduce percentage uncertainty?
Relevant Equations: -

Random error would be to do with not swinging the bung in a perfect circle so when I try to measure velocity, that would vary. Measurement of radius.

How would I decrease percentage uncertainty?
Use a smaller mass so that I get a larger radius so I can measure a longer length.
The problem here is that this appears to be part of your school work, and that YOU are the one who is supposed to come up with all the answers that you have asked here. So I'm not sure if you wish for us to confirm what you have written, or wanting us to tell you what other factors are involved in the uncertainty and errors in the experiment. The latter means that we will be answering and doing this part of your report for you.

Zz.
 

kuruman

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I viewed this on my laptop which I turned sideways, and I saw quite a few things missing in your post.
You want us to evaluate your efforts to understand your sources of error before you submit a report.
First, for that to happen how did you conduct the experiment? Its title is "Investigating circular motion", but all you show is a procedure. You need to show what you measured, explain how you measured it, discuss what sense you make of it and any provide additional information about measures you took to limit systematic error. In a nutshell, only you know what you did, why and how; more information is needed for us to comment on your methods.
Second, you mention a couple of sources of random error, not being able to swing in a perfect circle and measurement of the radius. Did you make an effort to see how reproducible your results are? Did you plot your results to see how much scatter there is from the predicted curve?
Third, you say that in order to reduce uncertainty (you need to) "Use a smaller mass so that I get a larger radius so I can measure a longer length." Why would that reduce uncertainty? You should be able to tell whether it did, considering that the procedure actually required you to use different masses. Were your results less uncertain when you used the smaller masses?

That's just for starters.
 
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@kuruman
The problem here is that this appears to be part of your school work, and that YOU are the one who is supposed to come up with all the answers that you have asked here. So I'm not sure if you wish for us to confirm what you have written, or wanting us to tell you what other factors are involved in the uncertainty and errors in the experiment. The latter means that we will be answering and doing this part of your report for you.

It's not a for a school report. I'm writing short summaries of potential investigations I could be asked to write about in my exam. The below is an example of the kind of things they'd want me to write in the exam. The procedure and analysis is something I didn't write out in detail because it's not hard to come up with it in the exam if I have a rough idea of what the experiment is. It's the uncertainty stuff that I struggle with which is why I want to know if the things I suggested are wrong and if there's anything else I can write for it.
I just found this question. It would be something like this. But sometimes they may ask what the errors are associated with such an experiment and how we can get more precise and accurate results and etc


QUOTE]
 
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kuruman

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It's not a for a school report. I'm writing short summaries of potential investigations I could be asked to write about in my exam. The below is an example of the kind of things they'd want me to write in the exam. The procedure and analysis is something I didn't write out in detail because it's not hard to come up with it in the exam if I have a rough idea of what the experiment is. It's the uncertainty stuff that I struggle with which is why I want to know if the things I suggested are wrong and if there's anything else I can write for it.
I just found this question. It would be something like this. But sometimes they may ask what the errors are associated with such an experiment and how we can get more precise and accurate results and etc
If your goal is to get good marks, then I suggest that you actually perform the experiment yourself and see first hand what the issues are with all the aspects of the experiment. What looks good on paper may not work as well in reality. There could be hidden pitfalls that you don't know are there until you fall in.
 
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If your goal is to get good marks, then I suggest that you actually perform the experiment yourself and see first hand what the issues are with all the aspects of the experiment. What looks good on paper may not work as well in reality. There could be hidden pitfalls that you don't know are there until you fall in.
My exams in three days...
 

kuruman

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My exams in three days...
Then perhaps you can do some research on the web. This is a standard experiment and I am sure you will find several write ups, videos and perhaps descriptions of the issues associated with it. Good luck on your exams.
 
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Then perhaps you can do some research on the web. This is a standard experiment and I am sure you will find several write ups, videos and perhaps descriptions of the issues associated with it. Good luck on your exams.
Thanks. How do I delete/close this thread?
 

berkeman

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Thanks. How do I delete/close this thread?
No need to delete the thread, but I can close if for you if you want. PM me if anybody wants it re-opened or wants to post a follow-up. Thanks for everybody's contributions to helping the OP.
 

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