Physics: Post your doubts here!

[6Astarstudent]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s12_qp_12.pdf
Ok so I'm done with every single thing except this question which is literally haunting me :'( plzzz plzzzz plzzzz if some1 knows it answers it pleaseeeeee it's Q:30

ok first you find the wavelength λ which is 2x the distance between 2 antinodes X and Y. so
λ= 2x 33cm = 66cm = 0.66m
and then v=f λ so f= v/ λ=330/0.66=500
we know that period (T) = 1/f = 1/500 = 0.2ms for 1 oscillation
so answer is B

 

[Zarif009]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_11.pdf

Question 6
This is the only problem i have out of the entire Question Paper someone please solve this thanks

 

[6Astarstudent]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w12_qp_11.pdf

Question 6
This is the only problem i have out of the entire Question Paper someone please solve this thanks

The question states that "X is measured with a percentage uncertainty of ±1 % of its value at all temperatures." meaning that the percentage uncertainty is unchanged, so A and B is eliminated.
then you need to apply some logic here, will the actual uncertainty get bigger as you approach 100 or 0?.
you can quickly do some math here, 100x1% = ±1 uncertainty while 0x1% = 0
so answer is C, least actual uncertainty when temperature close to 0

 

[Zarif009]

The question states that "X is measured with a percentage uncertainty of ±1 % of its value at all temperatures." meaning that the percentage uncertainty is unchanged, so A and B is eliminated.
then you need to apply some logic here, will the actual uncertainty get bigger as you approach 100 or 0?.
you can quickly do some math here, 100x1% = ±1 uncertainty while 0x1% = 0
so answer is C, least actual uncertainty when temperature close to 0

The question states that "X is measured with a percentage uncertainty of ±1 % of its value at all temperatures." meaning that the percentage uncertainty is unchanged, so A and B is eliminated.
then you need to apply some logic here, will the actual uncertainty get bigger as you approach 100 or 0?.
you can quickly do some math here, 100x1% = ±1 uncertainty while 0x1% = 0
so answer is C, least actual uncertainty when temperature close to 0

Wow thank you so much i should've read the question more carefully. Didn't see that percentage uncertainty is the same!

 

[TaffsAsLevel]

Two springs P and Q both obey Hooke’s law. They have spring constants 2k and k respectively.
The springs are stretched, separately, by a force that is gradually increased from zero up to a
certain maximum value, the same for each spring. The work done in stretching spring P is WP,
and the work done in stretching spring Q is WQ.
How is WP related to WQ?
A WP =
 0.25WQ B WP = 0.5
 WQ C WP = 2WQ D WP = 4WQ

How can it B???? Common sense it should be C but why markscheme said B?@?@?

OH MY GODDD NEVERMIND

first we need to find out the extension for both the springs
force is the same for both the springs that is equal to 'F'
force for P F=2k*x
x=F/2k
force for Q F=kx
x=F/k
Wp=1/2*k*x^2=1/2*2k*(F/2k)^2
Wq=1/2*k*x^2=1/2*k*(F/k)^2
Wp/Wq=1/2*2k*(F/2k)^2÷1/2*k*(F/k)^2
Wp=1/2Wq Ans

 

[1597.2217]

Good Luck everyone. There isn't anytime to clarify any more doubts, so just memorize the answer of what you find hard. Good luck again, remember me in yours prayers. Will really need them for P1s.

@Lyfroker
@IGCSEstudent2012

Good luck In sha Allah. Please remember me in yours prayers.

 

[Manobilly]

I have a tiny question in elastic collisions ,if one particle stops and other moves is it elastic? And if both move thn?

 

[1597.2217]

I have a tiny question in elastic collisions ,if one particle stops and other moves is it elastic? And if both move thn?

In inelastic collision, the momentum is conserved and Ek is lost. In elastic collisions, both values are conserved. Just remember that most of the collisions are inelastic except for in nuclear reactors which is elastic. You can calculate the Ek by 0.5 x m x v^2 for before and after collision if you're unsure about it.

Good luck!

 

[Kyusam]

ok first you find the wavelength λ which is 2x the distance between 2 antinodes X and Y. so
λ= 2x 33cm = 66cm = 0.66m
and then v=f λ so f= v/ λ=330/0.66=500
we know that period (T) = 1/f = 1/500 = 0.2ms for 1 oscillation
so answer is B

Thank you so much so so much

 

[1597.2217]

How was the exam?

hahahahahahahahaha......... There was a bad overall from my center, I expect between 25-30 myself. Left 4 due to time, 18, 23, 36 and another I cannot remember. Just randomly marked at the end, hoping that all of them are right.

 

[Imran Aasaf Kahout]

My question is somewhat odd and not related to any notes.

The problem is that i forgot to shade my candidate number on the physics multiple choice answer sheet and that has really got me worried. Though my name was written and i did sign, i can't get rid of this gnawing feeling at heart that my test may not be marked.

Does anybody here have had the same experience as me or knows what happens when a situation like this occurs?

 

[1597.2217]

That is bad. The computer will reject the paper and it will be manually graded. It depends on the examiner if he deducts five penalty marks or none. You can just pray now

 

[cheemaboyz]

can anyone help m with 9702_w10_qp_21
question no 3 part C
plz help

 

[Muhammad Harris]

I'm taking AS this oct/nov session. I need someone to help me with the following questions.
Here are the questions: oct/nov 2010 paper 13
Q2,3,5,12,17
Thanks in advance.

 

[◄Street Reader►]

Triangle law of adding vectors!!!???????????????
wats Disss I m not able to understand! HELPPPPPPPPPPPPPPP

 

[waleedsmz]

Why don't you guys link the paper? Be a little helpful.

 

[waleedsmz]

Triangle law of adding vectors!!!???????????????

wats Disss I m not able to understand! HELPPPPPPPPPPPPPPP

What exactly is your problem? Be a little more specific and it'd be great if you could link an example.

 

[◄Street Reader►]

its ok i m now familier wid dis !

What exactly is your problem? Be a little more specific and it'd be great if you could link an example.

 

[Muhammad Harris]

I'm taking AS this oct/nov session. I need someone to help me with the following questions.
Here are the questions: oct/nov 2010 paper 13
Q2,3,5,12,17
Thanks in advance.

Here is the link for the previous post. Hope anyone can help me.
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_13.pdf

 

[waleedsmz]

Here is the link for the previous post. Hope anyone can help me.

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_13.pdf

2) The time period of the wheel is 0.02s. To show it clearly on an oscilloscope you'd need 0.01s/cm, which is B.

3) Large systematic error means that there is an error in the tools you're using for example, so it measures a completely different value from what you're trying to reach. This cancels A and B. Small random error means that the readings have a small difference between them, so the answer is C.

5) The function is increasing ( with a decreasing rate ). So the difference between the function values ( Y axis ) intervals as the X increases, actually decreases.

In other words, if you draw tangents to the curve you'll find that they're getting less steep as the function continues. This again, indicates that the difference between 8 and 7 for example, is smaller than the difference between 2 and 1 (at which the curve is steeper). So the answer is C.

12) You need a relation that puts final speed, initial speed, acceleration and distance since those are the given ones.
V^2 = U^2 + 2as is the required one. V = 0 in both cases.
u^2 = -2ax ( notice that a is negative since it's deceleration )
(1.2u)^2 = -2aS
divide the two equations to find the value of S. It'd give C.

17) I don't really get this question to be honest. But it's dealing with the rate of change of energy ( aka power ). So I assume A and B are neglected, which leaves us to C and D. C completely ignores the other mass so it can't possible be the answer, since the motor should have higher power if it'd lift the elevator without the supporting mass. So the answer is D.