Physics: Post your doubts here!

[Haya Ahmed]

Suchal Riaz I'm waiting for the diagram of http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_23.pdf
Q1 e i and ii

 

[DeViL gURl B)]

well .. internal energy is the sum of the random KE and PE of all particles of a substance
KE depends on the temperature and PE depends on molecular sepration
So when temp increase ... KE increase so Internal energy increase and vice versa and same goes to the PE ... more te molecular sepration more PE more internal energy

So we can say that when a solid turns into a liquid .. The internal energy increases cuz there is an increase in the temp as well as the molecular separation. Right?

 

[princeali97]

IS THIS OK?

 

[ZaqZainab]

can anyone please explain Q4 c ii) 2. from
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_22.pdf

P.E=mgh
weight=mg
so P.E=weight*height

 

[Haya Ahmed]

So we can say that when a solid turns into a liquid .. The internal energy increases cuz there is an increase in the temp as well as the molecular separation. Right?

Yep ..

 

[doremon]

IS THIS OK?

which year is this from?

 

[ZaqZainab]

IS THIS OK?

i would say yes

 

[Haya Ahmed]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_23.pdf
Q 1 e both i and ii
and Question 2 a ii

 

[Suchal Riaz]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w12_qp_23.pdf

Q1 e (i),(ii) should we convert the speed into forces ? please someone explain ! .. thanks

Suchal Riaz

now use the cosine rule. angle is 90+45. scale drawing will not give accurate result because the velocity of wind gives 1.8cm only if i took 1 cm = 20 m/s

 

[_Ahmad]

it's simple. you already know the weight of the load just simply multiply it with the extension(17.8-16.3)

but I am not getting the answer

 

[doremon]

can someone please help me with phase difference?

 

[Suchal Riaz]

kitkat <3 :P
Please solve them simultaneously i have to solve other doubts

 

[kitkat <3 :P]

now use the cosine rule. angle is 90+45. scale drawing will not give accurate result because the velocity of wind gives 1.8cm only if i took 1 cm = 20 m/s

but the arrowhead is in different direction :/ i mean wont it affest the triangle

 

[kitkat <3 :P]

kitkat <3 :P
Please solve them simultaneously i have to solve other doubts

sure

 

[unique111]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s13_qp_22.pdf

Question 5b iii

 

[doremon]

but I am not getting the answer

change in gravitational potential energy = 3.8*1.5*10^-2(because extension is in centimetre)

 

[Haya Ahmed]

now use the cosine rule. angle is 90+45. scale drawing will not give accurate result because the velocity of wind gives 1.8cm only if i took 1 cm = 20 m/s

But the question didn't ask for drawing such diagrams ! I did this way and got the answer ! but I'm not sure did this answer 1 e (i) or not ! please someone correct me If I'm wrong !

Suchal Riaz

 

[_Ahmad]

change in gravitational potential energy = 3.8*1.5

What about the second part (2.)

 

[Snow Angel]

srry

Snow Angel
question number 4 (b) (iv)
current = 0.24 A
(a) p.d = IR = 0.24*5.5=1.32V
(b) terminal p.d = emf - lost volts = 4.4 V - (0.24 A * 2.3 ohm) = 0.552 V
(c) terminal p.d = emf - lost volts = 2.1 V - (1.8 ohm * 0.24 A) = 1.67 V

can u plz explain

why do they add the emf and the lost volts to find the terminal pd of cell B the answer is 2.1+(1.8*0.24)=2.53

 

[Suchal Riaz]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w12_qp_23.pdf
Q 1 e both i and ii
and Question 2 a ii

acceleration = gsin15
AB = 0.26/sin15=1.0
s=ut + 1/2 at² as u=0, s=1/2 at²
√(2s/a)=t
t= √( ( 2*1 )/ gsin15) = 0.89s