Author Topic: ALL CIE PHYSICS DOUBTS HERE !!!  (Read 171660 times)

Offline $!$RatJumper$!$

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #375 on: November 14, 2010, 03:07:13 pm »
Because at 30m, it has an initial velocity, whereas ur equation assumes initial velocity is 0  (ut=0)

i remember reading it off a book, so i think yeah thats true.


But then by doing the method you mentioned, arent we also assuming that initial velocity for the 30m is zero?

Offline Deadly_king

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #376 on: November 14, 2010, 03:14:46 pm »
Thank you :)
so why cant we do this: 10 = 0.5 * 9.81 * t2?
and so the ratio of the two gives the speed of them?

You cannot use this equation since you'll be finding the time taken to cover the first 10m of the fall, which is not the required answer ;)

TJ-56 described the appropriate method. :)

Ok Alpha.........am gonna go rest a bit now.

Good luck for the exams tomorrow guys. :D

Offline $!$RatJumper$!$

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #377 on: November 14, 2010, 03:19:31 pm »
You cannot use this equation since you'll be finding the time taken to cover the first 10m of the fall, which is not the required answer ;)

TJ-56 described the appropriate method. :)

Ok Alpha.........am gonna go rest a bit now.

Good luck for the exams tomorrow guys. :D

OK yeah i see how he did it :) it makes sense thankx

Offline $!$RatJumper$!$

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #378 on: November 14, 2010, 03:20:06 pm »
W05 Q 24 (URGENT please)

W06 Q25

S07 Q23

Offline TJ-56

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #379 on: November 14, 2010, 03:45:29 pm »
I need help with the following pls

W06 Q25
S06  Q9 & Q33
S07 Q23
W07 Q35
S08 Q6 & Q12
W09 P11 Q17 Why is it C and not D

Sorry for all the questions but these are all i have, thanx for any help, rly appreciated

Offline TJ-56

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #380 on: November 14, 2010, 03:55:26 pm »
W05 Q 24 (URGENT please)

W06 Q25

S07 Q23

W05 Q 24
Frequency P = 1/T = 1/ t20
So I is proportional to A2/T2
I0 / I(new) = ( x20/t20 ) / ( (2x)20/(2t)20 )
Simplifying would give I0, since both the time T and amplitudes are doubled , and since they are squared, they cancel each other out, and its back to the original so B

W06 Q25
I dont know it either, sorry

S07 Q23
Have doubts about that too


« Last Edit: November 14, 2010, 04:59:48 pm by TJ-56 »

Offline $!$RatJumper$!$

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #381 on: November 14, 2010, 06:34:49 pm »
I need help with the following pls

W06 Q25
S06  Q9 & Q33
S07 Q23
W07 Q35
S08 Q6 & Q12
W09 P11 Q17 Why is it C and not D

Sorry for all the questions but these are all i have, thanx for any help, rly appreciated


I need help on these too :( Someone?

Offline TJ-56

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #382 on: November 14, 2010, 06:44:47 pm »
I need help on these too :( Someone?

Those are rly important, some1 help

and did u understand q24 RatJumper?

Offline Dania

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #383 on: November 14, 2010, 07:15:19 pm »
Completely lost on this one!
:)

Offline $!$RatJumper$!$

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #384 on: November 14, 2010, 07:30:09 pm »
Those are rly important, some1 help

and did u understand q24 RatJumper?

i did thank you buddy :)

Offline $!$RatJumper$!$

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #385 on: November 14, 2010, 07:31:18 pm »
S03 Q22 :S

Offline TJ-56

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #386 on: November 14, 2010, 07:38:07 pm »
S03 Q22 :S

Think of it this way: if it were just 1 spring at the beginning, the extension is 3x, since they are 3, the extension is x
1 is removed, so now its 3x / 2 , which is 1.5x
The load is doubled, so 2 * 1.5x
Which is 3x, response D.
Hope that was clear, i understood it that way

Offline $!$RatJumper$!$

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #387 on: November 14, 2010, 07:47:28 pm »
Thankx :)

Offline Dania

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #388 on: November 14, 2010, 09:00:47 pm »
Anyone?
The answer is B.
:)

Offline TJ-56

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #389 on: November 14, 2010, 09:47:42 pm »
Anyone?
The answer is B.
Energy= mgh
The distance is halved
And the mass is also halved, because half move into the other vessel
so mgh/4