A2 Physics Unit 4 and 5 Revision Thread
Physics exam discussion - share revision tips in preparation for GCSE, A Level and other physics exams and discuss how they went afterwards.
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Re: A2 Physics Unit 4 and 5 Revision ThreadThe answer is A.(Original post by jgmuzic)
Hi, was wondering if anyone could help me out on a small question - unit 4 aqa, multiple choice.
When the length of a simple pendulum is decreased by 600mm, the period of oscillation is halved. What is the original length of the pendulum?
A-800mm
B-1000mm
C-1200mm
D-1400mm
I don't do maths for a level, as you might have guessed. Is this something to do with proportions or rearranging the simple pendulum equation?
Any feedback is appreciated.
We know that T=
To To = original period of oscillation.
We also know that L = Lo -600x10^-9 Lo = original length.
So T =To = 2
We also know that To =2
= 4 
=
= 
Lo = Lo - 600x10^-3 600x10^-3 = 
Lo
Lo = 0.8m = 800mm -
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Re: A2 Physics Unit 4 and 5 Revision Threadaqa phys 5 turning points question if any of you can help
for special relativity questions involving time dilation, length contraction and the mass energy equivalence, is the t0 or l0 the view of the observer or the actual particle? -
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Re: A2 Physics Unit 4 and 5 Revision ThreadDo you have more notes?(Original post by babuchang)
Hey, this should help for the relativity stuff... -
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Re: A2 Physics Unit 4 and 5 Revision Threadhttp://cid-5432f573d3fc3f5a.office.l...hysics%20Q.doc(Original post by Smithy-92)
Looking for as many questions as possible for Astrophysics.. anyone help with that??
http://cid-5432f573d3fc3f5a.office.l...hysics%20A.doc
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Re: A2 Physics Unit 4 and 5 Revision ThreadWelcome. Edexcel- Old syllabus.(Original post by Smithy-92)
Thanks very much! I assume since you just came across them again, you don't remember where they're from/what spec they belong to/etc? -
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Re: A2 Physics Unit 4 and 5 Revision ThreadCheck these too.(Original post by Smithy-92)
Looking for as many questions as possible for Astrophysics.. anyone help with that??
http://www.khanacademy.org/#cosmology-and-astronomy -
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Re: A2 Physics Unit 4 and 5 Revision ThreadYou know the equation
Q = Qoe^-t/RC
and that time constant = RC
This is a stupid question maybe, but doesnt that mean that -t/RC in the first equation = 1?
Or is the t in the original equation the time that has passed by? Or something differentLast edited by RSM93; 09-06-2011 at 18:56. -
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Re: A2 Physics Unit 4 and 5 Revision ThreadRC is the time constant, as you said. The amount of charge left, in the capacitor, is 0.367 (e^-1) it's original value (at t= 0) So yes, -t/RC = 1(Original post by RSM93)
You know the equation
Q = Qoe^-t/RC
and that time constant = RC
This is a stupid question maybe, but doesnt that mean that mean -t/RC in the first equation = 1?
Or is the t in the original equation the time that has passed by? Or something different
Once t = RC the amount of charge fall by 36.7% of the orginal value. -
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Re: A2 Physics Unit 4 and 5 Revision ThreadThanks(Original post by Summerdays)
RC is the time constant, as you said. The amount of charge left, in the capacitor, is 0.367 (e^-1) it's original value (at t= 0) So yes, -t/RC = 1
Once t = RC the amount of charge fall by 36.7% of the orginal value.
seems simple when you understand it 
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Re: A2 Physics Unit 4 and 5 Revision ThreadYeah which ones do you want? Astro, medical?(Original post by Summerdays)
Do you have more notes? -
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Re: A2 Physics Unit 4 and 5 Revision ThreadDo you have astro and the mandatory AQA unit 5 topic?(Original post by babuchang)
Yeah which ones do you want? Astro, medical?
seems simple when you understand it 
