Physics: Post your doubts here!

[bludlynsolja]

ok to be honest i have forgotten about moments or maybe am too tired to do it right now so maybe tomorrow or f someone else can help, that is number 3.
also number 6 for some reason i used to not have an explanation as to why the answer was so but always when asked such questions, u just have to describe the atom like its empty space and it is dense etc.
i used to not know the real reason tbh bt i used to just write that coz whenever such questions come, that is usually the answer.
u will find the notes for the atom on ur text book, bt reason why thats the answer, i really font kn =w maybe if someone can assist.
thx.

 

[Lucas Lee]

Hello, and thanks in advance : D
I am taking AS physics and have some questions.

1. What are the conditions for a formation of a stationary wave: e.g same speed and frequency but what else?

2. What is the difference between a potential divider circuit and a potentiometer?
iiwhat is the difference between a rheostat and a variable resistor

3. If we have a variable resistor and a fixed resistor connected to a e.m.f, How do we find which resistance of the variable resistor will give MAXIUM power usage to it?

 

[Camille96]

Help with june 2013 no. 6 b (i) and c (ii)
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s13_qp_42.pdf

 

[Camille96]

check

http://physics-ref.blogspot.com/2014/07/9702-june-2013-paper-42-worked.html

if it's still not clear, ask there

Thank you

 

[Faaiz Haque]

Q5 a ii and iii) With proper explanation.
Q6 c i and ii)2. with explanation again pleaseeee
ty
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w11_qp_22.pdf

 

[Faaiz Haque]

check at http://physics-ref.blogspot.com/2014/08/9702-november-2011-paper-22-worked.html

explanations are available

Woww, this site is awesome. Thanks so much
Can you send me a link to ALL of the papers done?

 

[robinhoodmustafa]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s06_qp_2.pdf
Q1 C (ii)

V2-U2 = 2as

Initial is zero as it is dropped from rest. you need the final velocity
Acc of free ( or you may call it g) is always -9.81 whether No Air resistance or Air resistance
Distance is 4.5
so input it

V2= 2 (9.81) (4.5)
Dont forget to take root.. I even missed the V2 would go on the other side and Square root
V=9.4 ms-1

 

[asadalam]

(b) The line of action of the weight W of the rod passes through the cord at point P.
Explain why, for the rod to be in equilibrium, the force F produced at the hinge must also
pass through point P?
How do we solve this?If all forces pass through a specific point,they have zero moment?How to explain this?
Awesome12 F.Z.M. 7 Dark Destination

 

[PlutoHuman]

How to do this question?

 

[asadalam]

check qu 13 at
http://physics-ref.blogspot.com/2014/10/physics-9702-doubts-help-page-2.html

Could you elaborate?If all the forces pass through a specific point the net moments or forces are zero?Can you explain this much?

 

[asadalam]

i have added some details. look at them there

So if all forces pass through one point,the system will be in equilibrium?regardless of force magnitude?

 

[asadalam]

yes, in this case. but not always. this condition does not imply translational equilibrium (don't worry about this if you don't understand)

At A-Level, the explanation in terms of moments I gave can be deduced

Ok,so at AS level we just have to look at the direction and if they intersect its in equilibrium?

 

[PlutoHuman]

look at qu 14 at

http://physics-ref.blogspot.com/2014/10/physics-9702-doubts-help-page-2.html

Can u explain how are the wires in parallel?

 

[Lucas Lee]

the first qu is answered as qu15 at
http://physics-ref.blogspot.com/2014/10/physics-9702-doubts-help-page-2.html

the others will be answered later

thank you : D. for the formation of stationary waves, do the waves need some kind of phase difference to form, like if it is formed from reflection, what would you call the phase thhat they meet at if this makes sense

 

[Lucas Lee]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w11_qp_22.pdf
Hello, can someone explain the answer to 5b and why it results into a current. Thanks, i get the other parts to the question

 

[SIstudy]

V2-U2 = 2as

Initial is zero as it is dropped from rest. you need the final velocity
Acc of free ( or you may call it g) is always -9.81 whether No Air resistance or Air resistance
Distance is 4.5
so input it

V2= 2 (9.81) (4.5)
Dont forget to take root.. I even missed the V2 would go on the other side and Square root
V=9.4 ms-1

umm could yu explain the next part of the question
that is exactly what I asked fr

 

[SIstudy]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_21.pdf
Q1 b (ii) plis

 

[SIstudy]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_21.pdf
Q3 b (ii)
I knw you've done this ppr Physicist
but I couldn't get it
pls solve this fr me
thanks In advance

 

[JackAaron]

can anyone explain Physics Paper 4 M/J/2005 Qn. 7 c) asap thanks

 

[JackAaron]

and Physics Paper 4 M/J/2009 qn. 9 b)