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Physics: Post your doubts here!

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Number 1 part (b)

i don't understand how to draw this current vector diagram and unable to resolve. pls help

a vector diagram will be appreciated.

Thanks
This question can be solved using parallelogram rule.
https://www.xtremepapers.com/community/attachments/capture1-png.10278/
To find the resultant magnitude, there are two ways:
- you have a rule don't you? Use it to measure the relative length of the forces. Force magnitude ratio equals diagram length ratio. Use the ratio to calculate. This is the "unprofessional" way but it works. :p
- use purely mathematics to calculate the force. Resolve the two forces and you get for the 6N, x-component is 6 cos40, y-component 6 sin40. The 8N, x-component 8, y-component 0. So the resultant x-component = 8 + 6 cos40, y-component 6 sin40.
Resultant magnitude, using Pythagorean Theorem, is sqrt [(8 + 6 cos40)^2 + (6 sin40)^2].
Answer should be 13.2N
 
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phy p2 nov 2012 p22.png

i used formula P=V^2/R and got the ratio 1.6....while in MS P=VI is used nd the option of V^2/R is given but the ans is 0.6 which is obtained only by P=VI....Where am i wrong???
 
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NIM

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Need help for question b ii but check if I'm right for i
 

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question 1(b)

the diameter of the wire is found to be 0.50 + or - 0.02mm.Calculate % uncertainty in
(1) the diameter
(2)the area of cross_section of the wire
 

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Hey.. The equation states r(^2) but they didn't include it in the calculation.... that always seems to be the case in other problems as well. Can someone please explain this to me? Thanks! :)
 

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Hey.. The equation states r(^2) but they didn't include it in the calculation.... that always seems to be the case in other problems as well. Can someone please explain this to me? Thanks! :)
Which book is that? :) Is it like a revision guide or work book? and if so is it helpful?
Please could you give me the name and cover of the book? :p
 
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Hey.. The equation states r(^2) but they didn't include it in the calculation.... that always seems to be the case in other problems as well. Can someone please explain this to me? Thanks! :)

they are asking abt electric potential energy whereas the formula u r talkng abt is the formula for electric Force...
 

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