# Isaac Physics helpWatch

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#1
you obtain the following results for the time period of a pendulum: (561,563,569,562,565)ns. None of these results are anomalous. You are then told that the accepted value is 560.5ns. Does this lie within your error bars?

I got the average of 564 and the uncertainty of +/- 4
I put yes but it said incorrect
what have I done wrong?
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1 year ago
#2
(Original post by yusyus)
you obtain the following results for the time period of a pendulum: (561,563,569,562,565)ns. None of these results are anomalous. You are then told that the accepted value is 560.5ns. Does this lie within your error bars?

I got the average of 564 and the uncertainty of +/- 4
I put yes but it said incorrect
what have I done wrong?
hm i'm actually not too sure on this one. So I did half the range 0.5*(569 - 561) = 4 to get the absolute uncertainty, and I think you've done the same. So the range should be 560 - 568. I'd have put Yes as well tbh. maybe isaac physics is wrong on this one ? Your method seems pretty sound. sorry i couldn't be much help.
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#3
(Original post by levi ackerman)
hm i'm actually not too sure on this one. So I did half the range 0.5*(569 - 561) = 4 to get the absolute uncertainty, and I think you've done the same. So the range should be 560 - 568. I'd have put Yes as well tbh. maybe isaac physics is wrong on this one ? Your method seems pretty sound. sorry i couldn't be much help.
no problem, I hate uncertainty tbh are you a uni student btw? or doing A level?
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1 year ago
#4
(Original post by yusyus)
no problem, I hate uncertainty tbh are you a uni student btw? or doing A level?
Yeah, it's a weird topic. There's not a lot of questions to practice from, which is a pain.

Currently in year 13
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#5
(Original post by levi ackerman)
Yeah, it's a weird topic. There's not a lot of questions to practice from, which is a pain.

Currently in year 13
ahh same which board are you doing?
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1 year ago
#6
I don't think they meant uncertainty when they said error bars, error bars have a formula for which you need to calculate the standard deviation if I recall correctly.
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1 year ago
#7
do you know the length of the thread on which the ball is attached to???
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1 year ago
#8
(Original post by yusyus)
ahh same which board are you doing?
AQA. it's not too bad actually
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1 year ago
#9
(Original post by yusyus)
you obtain the following results for the time period of a pendulum: (561,563,569,562,565)ns. None of these results are anomalous. You are then told that the accepted value is 560.5ns. Does this lie within your error bars?

I got the average of 564 and the uncertainty of +/- 4
I put yes but it said incorrect
what have I done wrong?
You need to draw a graph for error bars as far as I know
0
1 year ago
#10
if you know the length of the thread, the best thing to do is to cheat the way out use the formula :
2pi square root of length over acceleration due to gravity which is 9.80 ms-2 (in chicago)
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#11
I don't think they meant uncertainty when they said error bars, error bars have a formula for which you need to calculate the standard deviation if I recall correctly.
ahh, ive never done anything like that in physics so I guess its past the scope of my spec.
Im just thinking of it as one error bar though because time period is usually avaraged and plot once per ... values so idk how it wouldn't lie in the error bar (s)?
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#12
(Original post by OMG354)
if you know the length of the thread, the best thing to do is to cheat the way out use the formula :
2pi square root of length over acceleration due to gravity which is 9.80 ms-2 (in chicago)
nah all of the given information is there, I think this question is more based on the uncertainty method than anything anyway
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1 year ago
#13
(Original post by yusyus)
ahh, ive never done anything like that in physics so I guess its past the scope of my spec.
Im just thinking of it as one error bar though because time period is usually avaraged and plot once per ... values so idk how it wouldn't lie in the error bar (s)?
do wat i told you m8
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1 year ago
#14
I don't think they meant uncertainty when they said error bars, error bars have a formula for which you need to calculate the standard deviation if I recall correctly.
ahh that must be it then. I think using absolute uncertainty = error bars worked for a couple of the other Yes/No questions which were similar to this one, so they must've worked by coincidence then.

But it does sound a bit beyond A-level
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#15
(Original post by G.Y)
You need to draw a graph for error bars as far as I know
right, but idk what of; all of the information in the question I wrote in the original question. In experiments about time period and a pendulum isn't it that one length is used and then repeats are taken like the ones in the question, then you take the average and the uncertainty and plot graphs from it by changing the length of the string only.
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#16
(Original post by levi ackerman)
AQA. it's not too bad actually
I do AQA too, are you going for an A*?
tbh I don't mind AQA I think Edexcel is easier; the last years experimental paper for AQA i found like impossible and the grade boundaries were super low
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1 year ago
#17
(Original post by yusyus)
I do AQA too, are you going for an A*?
tbh I don't mind AQA I think Edexcel is easier; the last years experimental paper for AQA i found like impossible and the grade boundaries were super low
yeah, hopefully!
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#18
(Original post by levi ackerman)
yeah, hopefully!
how are you revising this holiday? I just had no ideas so I'm just gonna go through the AQA map on Isaac physics till term starts.
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1 year ago
#19
(Original post by yusyus)
how are you revising this holiday? I just had no ideas so I'm just gonna go through the AQA map on Isaac physics till term starts.
I think I'm mostly just typing up my notes under easter ends, then doing exam questions until june :')
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#20
(Original post by levi ackerman)
I think I'm mostly just typing up my notes under easter ends, then doing exam questions until june :'
nice nice, feel free to send them if you wana
what uni you aiming for?
I need 2A* and an A so I really want one in Physics
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