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physics help

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paper 11 oct/nov 2009
question number 12...please can somebody explain why the tensions are not the same..?
 
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A/sina = B/sinb = C/sinc

where A,B, and C are the sides opposite the corresponding angles.
 
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ohhh i knew the theorm but not the name!!
haha i wont forget this now
u simple mean sine rule!!!
thanx !
 
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That was just in mathematics. Lami applied it into the forces context and it became the Lami's theorem in Physics :)
 
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ok i came across a few more problems.
this is paper 4 physics may/june 09 question no. 3 part ii...
why do we subtract the masses and the powers...i just couldn't figure this out.
same paper question 6 part c..a full explanation required of this one..actually my concept of this root mean square current thing is a bit weak so if somebody can explain this and cast light on the topic, i would be very thankful.
and sadly SAME paper question 9..(a) ii. how do you apply A=lambdaN here. also it's B part.

NOV/OCT paper 4 physics 08.
question 7 part c. wasn't able to solve this one. =/

yeah that is about it. zohaib sir i would really appreciate if you explain this in detail.
many thanks in advance.
 
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But we studies Lami's theorem in M1 back in AS.
its not included in the physics syllabus...
 
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Studied*. but still, i used simple sine rule. lami was too confusing :/
 
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http://notezone.net/cambridgechem/chemi ... sis%5D.pdf plz go dix link pg 11 n c answers below of it

First of all you need the mass of FA1. In the first table you have the mass of the empty test tube and the

mass of the test tube + FA1. All you do is subtract the values 12.80 - 10.50 giving you 2.30g of FA1.

In the second table you need the mass of FA1 after heating. Again, you just subtract the values 11.76 -

10.50 = 1.26g FA1 after heating.

1 d. (i) The mass of anhydrous XS04 present in the crystals is what is left over after heating = 1.26g

1 d. (ii) The mass of water driven from the crystals is the loss in mass that has occurred when the FA1 was

heated. Before heating there were 2.30g of FA1 and after heating there were 1.26g. So the mass of water

lost is 2.30 - 1.26 = 1.04g

1 e. To calculate the number of moles of water in the sample of FA1 you use the formula no. of moles =

mass/mass of 1 mole which gives you 1.04/18 = 0.058 mol

1 f. The number of moles in XSO4
7 moles of H20 gives 1 mole XSO4 (from the formula XSO4.7H20)
So 0.058 moles of water give 0.058/7 = 8.29 x 10 ^ -3 moles of XSO4

1 g. To calculate the relative formula mass of XSO4 you use the formula mass of 1 mole = mass/no. of

moles which gives you 1.26/8.29 x 10 ^ -3 = 152.7

1 h. To calculate the Ar of element X you first find the Mr of SO4 which is 32 + (4 x 16) = 96
You subtract this from the RFM from part g giving you 152.7 - 96 = 56.7
 
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