Physics, Chemistry and Biology: Post your doubts here!

[XxChampXx]

Someone help me solve part (c)...
View attachment 53895

Even I have a doubt in that

 

[XxChampXx]

Can someone please explain may june 2009 paper 31 question 9 part b(i) and (ii)
Link:- https://drive.google.com/folderview...sp=drive_web&tid=0BzumkDfi9230NFdPdmpOTjFfeHM
Thank you in advance

 

[XxChampXx]

Can someone explain oct nov 2011 qp 32 question 3 part c also
Link:- https://drive.google.com/folderview...sp=drive_web&tid=0BzumkDfi9230NFdPdmpOTjFfeHM
Thank you in advance

 

[Shandana khan]

Can someone please explain oct nov 2009 paper 3 question 9 part b(i) and (ii)
Link:- https://drive.google.com/folderview...sp=drive_web&tid=0BzumkDfi9230NFdPdmpOTjFfeHM
Thank you in advance

Paper 31 or 32..? The link u have provided is for may/June...not Oct/Nov.

 

[qwertypoiu]

Someone help me solve part (c)...
View attachment 53895

G3?

So yeah one of the conditions of equilibrium is no resultant force. Therefore forces up = forces down
Forces up = 8N
Forces down = 1.5N + 6N = 7.5N
These are not equal.
To make them equal there must be a force acting downwards, of magnitude 0.5N.

 

[Shandana khan]

Can someone explain oct nov 2011 qp 32 question 3 part c also
Link:- https://drive.google.com/folderview...sp=drive_web&tid=0BzumkDfi9230NFdPdmpOTjFfeHM
Thank you in advance

Hope u'll get it...

 

[Mustafa84922]

Someone help me solve part (c)...
View attachment 53895

its answer is 1.5 and the reason is simple
first of all leave the two weights 6N and 8N as we calculated in the last part they have equal moment so they cancel out each other
read the question carefully it says uniform rod, which means that the pivot is actually cancelling out the weight of 1.5 N and as the distance is equal the pivot is applying 1.5 N force upwards
hope im right

 

[Mustafa84922]

O/N 2005

lol i am wrong srry....... ill try to solve it again........

 

[Mustafa84922]

O/N 2005

G3?

So yeah one of the conditions of equilibrium is no resultant force. Therefore forces up = forces down
Forces up = 8N
Forces down = 1.5N + 6N = 7.5N
These are not equal.
To make them equal there must be a force acting downwards, of magnitude 0.5N.

YEA he is right i did not read your answer first i just directly replied to him
and i also forgot to use the upward forces and downward forces rule damnit im bad at physics.............

 

[Mustafa84922]

can anyone help me i got a* in my school exams in physics but now tomorrow is the paper and im not able to even solve the simplest questions -_-
and i asked a question from 2014 winter 31 it was about the volume of helium in an inflated balloon, can anyone give me COMPLETE explanation i mean everything like why do we use p1v1=p2v2, why does the mark scheme subtract the volume of helium in cylinder from the one calculated using p1v12v2
And one more thing how are you guys preparing for the exam book, past papers or notes? plz reply..........

 

[Iris Dylan Lane]

Anyone did 31?

I did

 

[amiz99]

was there an error in chemistry p11 or is it just me??

 

[XxChampXx]

Paper 31 or 32..? The link u have provided is for may/June...not Oct/Nov.

Sorry I needed may june not oct/nov. I edited my post

 

[XxChampXx]

Hope u'll get it...View attachment 53900

I understood the first two but the last part marking scheme says 5.24 and they subtracted 14.7 from 30.9(which I did not understand why)

 

[UsamaFTW]

yeah i wrote that but some of my friends suggests that it will produce co2 and water

It is CO2 and H2O. In the presence of oxygen it undergoes aerobic respiration. C2H5OH + 3O2 --> 2CO2 + 3H2O .

 

[Saad the Paki]

Could somebody do part (b)
Like a complete diagram please!

 

[Abdurrahmanmuhammed]

can someone help me ? explanation also please

 

[Iris Dylan Lane]

I understood the first two but the last part marking scheme says 5.24 and they subtracted 14.7 from 30.9(which I did not understand why)

Hope you don't mind me answering.
But for the force in F=ma, you take the resultant force.
There is an upward force acting on the brick, 14.7N and a downward force weight, (3.09 * 10N= 30.9)
Resultant force is 16.2N
16.2/3.09 = 5.24ms^2

 

[Iris Dylan Lane]

can someone help me ? explanation also pleaseView attachment 53903

Answer = D?

 

[Iris Dylan Lane]

Could somebody do part (b)
Like a complete diagram please!