IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: halosh92 on April 18, 2010, 03:55:05 pm
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COULD SOMEONE PLZ
just type in the exact rules for uncertainities and wat do we do in cases where is squring and cubing?
plz this is very urgenttttttttttttt
thx
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could you please be more precise??
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COULD SOMEONE PLZ
just type in the exact rules for uncertainities and wat do we do in cases where is squaring and cubing?
plz this is very urgenttttttttttttt
thx
whether its dividing or multiplyin, u need 2 add d % uncertainties....
if its squaring, dn multiply d % uncertainty by 2, n if its cubed multiply it by 3....
ignore constants....
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could you please be more precise??
i just need the rules thats all for uncertainity
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whether its dividing or multiplyin, u need 2 add d % uncertainties....
if its squaring, dn multiply d % uncertainty by 2, n if its cubed multiply it by 3....
ignore constants....
thx alottt :)
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thx alottt :)
ur welcum:)
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i have another few questions these are about practicals
1) sometimes they ask us to measure T period of oscillation what does that mean?>
do we measure the time for 10 oscillations and then divide by 10 to get T of one oscillation or do they mean T as in time for 10 not one
oscillation.
2)best fit line - does it have to be starting from the origin?
3)whats the maximum no.of large squares when plotting graph?
4)work to an accuracy of half a small square...wat does this mean
5)how to measure cirumference by using a string revolved around something
6) cross sectional area of a wire-the formula is pie r^2 correct?
THX ALOT
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could someone plz answer these questions?? :-\ :-\ :-\ :-\ :-[ :-[ :-[ :-[ :-[ :-[
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i have another few questions these are about practicals
1) sometimes they ask us to measure T period of oscillation what does that mean?>
do we measure the time for 10 oscillations and then divide by 10 to get T of one oscillation or do they mean T as in time for 10 not one
oscillation.
2)best fit line - does it have to be starting from the origin?
3)whats the maximum no.of large squares when plotting graph?
4)work to an accuracy of half a small square...wat does this mean
5)how to measure cirumference by using a string revolved around something
6) cross sectional area of a wire-the formula is pie r^2 correct?
THX ALOT
1) You can measure it once or ten times, but the more times you measure it, ie the longer the span, the more accurate the results are.
2) No it does not, it has to take in most points though. For example in biology, the line of best fit will not always come from the origin.
3) I did not understand
4) The half of the smallest square. So, if you have a number that is between two values, just put the point inside the small square.
5) Simple, just put the string around the small sphere, and make sure that it is of the largest possible distance. So that you have measured the circumference. Try this : String (http://www.google.com/url?sa=t&source=web&ct=res&cd=1&ved=0CAYQFjAA&url=http%3A%2F%2Fwww.fredonia.edu%2Forg%2Fprojectprime%2Fresources%2Flessons%2Fstringitalong.pdf&rct=j&q=how+to+measure+the+circumference+using+a+string&ei=eCzLS_rHI9Tj-QbEt5D4BA&usg=AFQjCNEsI09nsnQKwmErS2GS5yuO8LmYAQ&sig2=I8nQuFBdxK0QbpYtYURjdw)
6) Yes it is, because the cross section of a wire is a circle.
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1) You can measure it once or ten times, but the more times you measure it, ie the longer the span, the more accurate the results are.
2) No it does not, it has to take in most points though. For example in biology, the line of best fit will not always come from the origin.
3) I did not understand
4) The half of the smallest square. So, if you have a number that is between two values, just put the point inside the small square.
5) Simple, just put the string around the small sphere, and make sure that it is of the largest possible distance. So that you have measured the circumference. Try this : String (http://www.google.com/url?sa=t&source=web&ct=res&cd=1&ved=0CAYQFjAA&url=http%3A%2F%2Fwww.fredonia.edu%2Forg%2Fprojectprime%2Fresources%2Flessons%2Fstringitalong.pdf&rct=j&q=how+to+measure+the+circumference+using+a+string&ei=eCzLS_rHI9Tj-QbEt5D4BA&usg=AFQjCNEsI09nsnQKwmErS2GS5yuO8LmYAQ&sig2=I8nQuFBdxK0QbpYtYURjdw)
6) Yes it is, because the cross section of a wire is a circle.
for question 3) in the graph while choosing a scale each large square is 1 cm how many such large squares can we take when plotting our
scale like if our scale is 0,2,4,6,8..from 0 to 2 whats the max no,of squares we can take ???? and do we have to plot the zero
always even though we dont have it in our measurement sin the table??
THANKYOU SO MUCHHHHH
ive got a mock tomorrow..sorry for bothering u ;D ;D ;D
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could someone plz tell me how to calcualte the uncertainity of time in the practical???
and if i take the reading 3 times do i get the average of these readings and find the uncertainity..HOW EXACTLY?
and the ms they say take half the uncertainity??? :o ??? ???
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huh?
We take the smallest scale on the instrument
fractional uncertainty= +/- smallest unit/ value
if ur using a stopwatch, it usually has an error of +/- 0.01s
if ur using a watch, with the second hand, it has an error of +/- 1s
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huh?
We take the smallest scale on the instrument
fractional uncertainty= +/- smallest unit/ value
if ur using a stopwatch, it usually has an error of +/- 0.01s
if ur using a watch, with the second hand, it has an error of +/- 1s
alright wat if i have repeated the reading thrice??
and By the way for any gradient.....on a graph....do we have to write a unit for the gradient?
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alright wat if i have repeated the reading thrice??
and By the way for any gradient.....on a graph....do we have to write a unit for the gradient?
no...slope has no units usually...
unless for eg...they tell u...find acc from vel/time graph....then the slope is the acc....gttn it?
use the average value
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no...slope has no units usually...
unless for eg...they tell u...find acc from vel/time graph....then the slope is the acc....gttn it?
use the average value
YESS THANKX ALOT NID :D
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Great Nid..Helping others as always..
+rep.
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I'm helping ppl out in phy....phy is good...except the waves :-X
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I'm helping ppl out in phy....phy is good...except the waves :-X
lool..i think waves will once appear to you in night mares or smth :P lol
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lool..i think waves will once appear to you in night mares or smth :P lol
I won't mind until it can fathom as to what crap it is
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nid , AF, and astar . ure a gr8 bunch of help SERIOUSLY
i agree waves i spent 2 days doing papers and studing from like 7 books..until i got it PATHETIC
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nid , AF, and astar . ure a gr8 bunch of help SERIOUSLY
i agree waves i spent 2 days doing papers and studing from like 7 books..until i got it PATHETIC
:-[ :-[ :-[ lol Thank you halosh :D..but nid and Astar deserve all the credit :D...
plus her'es an AWESOME site for physics..and especially waves..animations, questions, and graphs overthere ar simply amazing..scroll down to the oscillations and waves part..dont hesitate to contact if u need help! :D
http://www.s-cool.co.uk/alevel/physics.html
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no A.F, ur awesome :)
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no A.F, ur awesome :)
:-[ :-[ Thank You Thank You lol ;D
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:-[ :-[ :-[ lol Thank you halosh :D..but nid and Astar deserve all the credit :D...
plus her'es an AWESOME site for physics..and especially waves..animations, questions, and graphs overthere ar simply amazing..scroll down to the oscillations and waves part..dont hesitate to contact if u need help! :D
http://www.s-cool.co.uk/alevel/physics.html
thx for the link dude
and i agree wid nid !!! ure awesome ;D ;D ;D
thx :D
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thx for the link dude
and i agree wid nid !!! ure awesome ;D ;D ;D
thx :D
lol Thank You..glad i helped ;D
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By the way !
in the practical when they say in the beginning of the experiment take the length of the rope of ABOUT 50cm
does that mean we have to take 50 or there is some sort of range?
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By the way !
in the practical when they say in the beginning of the experiment take the length of the rope of ABOUT 50cm
does that mean we have to take 50 or there is some sort of range?
Make it close to 50 cm as possible..
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if the uncertainity is 18.0 + or - 0.05 mm
do we have to change the 18 to m.... then find the percentage uncertainty?
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if the uncertainity is 18.0 + or - 0.05 mm
do we have to change the 18 to m.... then find the percentage uncertainty?
nope..if u've got all the values in one unit...then no need to change as long as u mention +- mm, m, cm, etc..