Physics: Post your doubts here!

[emkay]

lol.

Thanks dude ! Seems like you are good in physics !

not really just trying to get my self into it before i have a one on one battle with it

 

[A_K_D]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_23.pdf

7bii) I don't get why charged particle is not an isolated system

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_w11_qp_13.pdf

29) I just don't understand the question, I looked at examiners report and it said that the lines R to S has a constant phase difference

 

[Trisha Graal Emile]

1. A metal ball is dropped into a tall cylinder of oil. The ball initially accelerates but soon reaches a terminal velocity.

a. By considering the forces in the metal ball bearing, explain why it first accelerates but then reaches terminal velocity.

b. Describe how you would show that the metal ball reaches terminal velocity.

1.
A metal ball is dropped into a tall cylinder of oil. The ball initially accelerates but soon reaches a terminal velocity.

a. By considering the forces in the metal ball bearing, explain why it first accelerates but then reaches terminal velocity.

b. Describe how you would show that the metal ball reaches terminal velocity.

 

[queen of the legend]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s03_qp_2.pdf

Please someone help me for no. no. 3(a)(ii) and b(i)

for question 3aii : its very simple if u read the text book you can find detailed explanation about this topic, anyhow .. take a ruler and put it on the line of the graph so that when line starts deviating from straight path its the point that should be marked L where hook's law will not apply because force is no longer proportional to extension . in the next question it asks about the spring constant and since we know that f=ke where k is a constant. to deduce value of k from graph we know that k=f/e. the gradient of the graph is e/f so that k = 1/gradient

bi: the circumference of the circle is pi x d ...the change in length of the wire occurs over the pulley ...we know the pulley turns an angle 6.5 so the amount of increase or extension is = 6.5/360 x 3pi..............6.5/360 will give us the amount of increase at the circumference ..............i hope u understood !

 

[queen of the legend]

Another one..
Oct/Nov 2010 - QP 22 - Question 1 - part (b).

I have no idea about doing questions related to horizontal components, the ones with tan, etc.
Could someone give me a complete explanation of how to deal with such questions?

QP: http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_22.pdf
MS: http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_ms_22.pdf

Thanks.

but the question is not about component of vectors ?! its about uncertainty isnt it ?

 

[bamteck]

for question 3aii : its very simple if u read the text book you can find detailed explanation about this topic, anyhow .. take a ruler and put it on the line of the graph so that when line starts deviating from straight path its the point that should be marked L where hook's law will not apply because force is no longer proportional to extension . in the next question it asks about the spring constant and since we know that f=ke where k is a constant. to deduce value of k from graph we know that k=f/e. the gradient of the graph is e/f so that k = 1/gradient

bi: the circumference of the circle is pi x d ...the change in length of the wire occurs over the pulley ...we know the pulley turns an angle 6.5 so the amount of increase or extension is = 6.5/360 x 3pi..............6.5/360 will give us the amount of increase at the circumference ..............i hope u understood !

Hey thank you soo much

 

[bamteck]

http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_w05_qp_2.pdf

Someone please help me for no. 5 (c)(ii)

 

[AAAAAA]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w05_qp_2.pdf

Someone please help me for no. 5 (c)(ii)

find resultant amplitude and use relationship intensity is proportional to amplitude^2

 

[bamteck]

find resultant amplitude and use relationship intensity is proportional to amplitude^2

Please do it for me, I can't understand !

 

[bamteck]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s06_qp_2.pdf

Help needed for no. 6 (a)(i) and (c) and 7(a) (b) (c)

 

[Asheeta]

Hello, help needed for Nov 2010 paper 2 no.4 (b) the whole part
What is the region Es?? and how to find it?
please help and by the way can someone give a good definition for strain energy??

 

[Asheeta]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s06_qp_2.pdf

Help needed for no. 6 (a)(i) and (c) and 7(a) (b) (c)

no. 6
so just stretch the dotted lines till fig 6.2
the upperpart is the same as in fig 6.1
in the 32.4 cm just draw a loop
that's it.

(c)so after the sketch you see that you have antinode on the top then a node a loop and a node
dist between antinode and node = (lambda/4)
dist between 2 nodes = (lambda/2)
(lambda/2)=32.4
therefore (lambda/4)=16.2cm
this means that the antinode will be 0.5 cm above the tube

hope you've understood!

 

[bamteck]

no. 6
so just stretch the dotted lines till fig 6.2
the upperpart is the same as in fig 6.1
in the 32.4 cm just draw a loop
that's it.

(c)so after the sketch you see that you have antinode on the top then a node a loop and a node
dist between antinode and node = (lambda/4)
dist between 2 nodes = (lambda/2)
(lambda/2)=32.4
therefore (lambda/4)=16.2cm
this means that the antinode will be 0/5 cm above the tube

hope you've understood!

Hey thank you soo much

Btw, Strain energy is the energy stored in a body due to change of shape !

 

[AAAAAA]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s06_qp_2.pdf

Help needed for no. 6 (a)(i) and (c) and 7(a) (b) (c)

amplitude of wave A = 3 (maximum disp. from first graph)
amplitude of wave B=2

but phase difference between A and B is π radians.
It is said in the question that the waves are at a common point (point P)

therefore, from principle of superposition resultant amplitude = amplitude of A - amplitude of B

This is equal to 1

Intensity is proportional to amplitude squared

At A, intensity = I and amplitude=3
hence, I=k(3^2)
k=constant=I/9

so, if resultant amplitude is 1, intensity=k(1^2)

this is equal to I/9

this is for the NOV05 question..

Note: I have ignored factors of 10^-3 in amplitude because it would cancel out anyway.

 

[bamteck]

amplitude of wave A = 3 (maximum disp. from first graph)
amplitude of wave B=2

but phase difference between A and B is π radians.
It is said in the question that the waves are at a common point (point P)

therefore, from principle of superposition resultant amplitude = amplitude of A - amplitude of B

This is equal to 1

Intensity is proportional to amplitude squared

At A, intensity = I and amplitude=3
hence, I=k(3^2)
k=constant=I/9

so, if resultant amplitude is 1, intensity=k(1^2)

this is equal to I/9

this is for the NOV05 question..

Note: I have ignored factors of 10^-3 in amplitude because it would cancel out anyway.

Thank youuuuuuuuuuuuu

 

[bamteck]

http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_w06_qp_2.pdf

Please help me for no. 2(a) on how to get the gradient !
and for no. 7(b)
Thanks

 

[Kumkum]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_qp_21.pdf
Please help me with question number 7(b)(i) and (ii), and also (c), and question number 5(a) and (b).

 

[Asheeta]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w06_qp_2.pdf

Please help me for no. 2(a) on how to get the gradient !
and for no. 7(b)
Thanks

So for the gradient just draw a tangent at t=0.8 s and use 2 points.

7(b) (i) Kirchoff's first law states that the sum of currents arriving a junction = the sum of currents leaving the junction
therefore, I1+I2=I3

(ii) 1. 2nd law is that the sum of emfs around any closed circuit = the sum of pds . Therefore,
E2 = I2R2 + I3R3
2. E1 - E2 = I1R1 - I2R2

 

[Asheeta]

Hey ppl in paper 2 sometimes there is a number involving estimates of certain things for e.g the mass of a protractor- 10 g
could someone just list some quantities whose value must be learnt

 

[A_K_D]

Can someone Please Please Please answer my Question's (it got ignored 3 times)

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_23.pdf
7bii) I don't get why charged particle is not an isolated system

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_qp_13.pdf
29) I just don't understand the question, I looked at examiners report and it said that the lines R to S has a constant phase difference


I will thank you a lot