Author Topic: A2 physics p5  (Read 15384 times)

Offline Eye

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Re: A2 physics p5
« Reply #30 on: May 19, 2009, 08:39:21 pm »
How do you calculate the absolute errors in the second question of p5 and how do you draw the worst acceptable line?

Offline khagga_926

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Re: A2 physics p5
« Reply #31 on: May 19, 2009, 08:53:38 pm »
open this and check dat...start reading from half page 20-22

Offline Eye

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Re: A2 physics p5
« Reply #32 on: May 19, 2009, 09:01:08 pm »
Thanks bud.
(:

Offline taha12

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Re: A2 physics p5
« Reply #33 on: May 19, 2009, 09:17:20 pm »
Ok man this is how you go
in question 2 p5
suppose
I/V         V/V          lg(I/I)       lg(V/V)
2             4+/- 0.1
3            7+/- 0.1

you can simply calculate values of Log I example log 2 =0.301 write it in the column
lg(I/I)

for log V you calculate value  Log V example log 4= 0.602 write it in the column under lg(V/V)

absolute errors in lg (V/V):
error in V/V is +/- 0.1 thus absolute error in lg (V/V) would be *
take the first value in the group V/V which is 4
(log 4)  - (log 3.9) = 0.01 to 1 sig fig
       or
(log 4.1)- (log 4) = 0.01 to 1 sig fig
note that 3.9 or 4.1 value comes from subtracting or adding 0.1 from actual value which was 4 see column above of V/V
both ways are correct

same for the second value 7 +/- 0.1
log 7.1 - log 7.0
or
 log 7 - log 6.9

another example

100 +/- 20

you do for absolute errors

log 100 -log 80

or

log 120 -log 100

just remember to either add or subtract the error from actual value
tricky
if its square of distance

suppose d/cm = 2 cm+/- 0.1
the errors in "d square world be"
(2.1 square ) - 2.0 square
  or

2.0 square - 1.9 square

this would give you error
in this case d square = 4+/-0.4

hope it solves it all for every one



Offline bilalar

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Re: A2 physics p5
« Reply #34 on: May 19, 2009, 09:27:18 pm »
I/V         V/V          lg(I/I)       lg(V/V)
2             4+/- 0.1
3            7+/- 0.1


another way of calculatin the errors is :

lg 4 = 0.602

take (lg 4.1 - lg 3.9)/2
this will give  error +/- 0.01

this is easier and faster method

Offline taha12

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Re: A2 physics p5
« Reply #35 on: May 19, 2009, 09:30:30 pm »
the method is same just a small tweak with the rule
just remember to take into account the upper and lower limit ;)

Offline bilalar

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Re: A2 physics p5
« Reply #36 on: May 19, 2009, 09:32:39 pm »
yeah well the tweak really helps you, when you're runnin short of time 8)

Offline taha12

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Re: A2 physics p5
« Reply #37 on: May 19, 2009, 09:34:55 pm »
man are there any chances of a paper being leaked out ?
 :-\

Offline bilalar

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Re: A2 physics p5
« Reply #38 on: May 19, 2009, 09:40:02 pm »
the odds don't seem favourable so far

Offline mista.lova.lova

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  • ! rAwk!!
Re: A2 physics p5
« Reply #39 on: May 19, 2009, 09:44:48 pm »
wait for malaysia n newzealand thn... :d
! rAwk!!

Offline Eye

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Re: A2 physics p5
« Reply #40 on: May 19, 2009, 11:06:11 pm »
Great! Thanks Taha. I totally got that.
:)

Offline MichelleLiZ

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Re: A2 physics p5
« Reply #41 on: May 20, 2009, 05:53:15 am »
No news yet?

Offline taha12

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Re: A2 physics p5
« Reply #42 on: May 20, 2009, 07:20:19 am »
anybody there

Offline taha12

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Re: A2 physics p5
« Reply #43 on: May 20, 2009, 07:20:42 am »
???  :-\

Offline aisvo

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Re: A2 physics p5
« Reply #44 on: May 20, 2009, 07:30:38 am »
i'm writing it in 30 min.. wish me luck