Physics Paper 2

[usama1993]

hey guys....what was wrong with the last question in SEC B ?
I have read the whole syllabus but didnt found out anything mentioned about RECTIFIERS AND RECTIFYING CIRCUITS...
That why did they gave us to draw in examination?????
I did nothing about that part

 

[usama1993]

hey guys/......
why did they give the question on RECTIFIER CIRCUIT in Sec B last question when recitier has not been mentioned in the sylabus >?????

 

[Brains]

Yes the acceleration was supposed to be in negative.. because initial speed was 25m/s and final was 22m/s...
and the time taken was 0.0013s which if u put in the acceleration formula you get -2300m/s .....

but i have 2 questions...

in part a) of this question was the change in velocity '3' or '-3'?

in part c) we had to apply F=ma ... in which we had to change the acceleration to poisitive because force cannot be in negative???

 

[Prince III]

Yes the acceleration was supposed to be in negative.. because initial speed was 25m/s and final was 22m/s...
and the time taken was 0.0013s which if u put in the acceleration formula you get -2300m/s .....

but i have 2 questions...

in part a) of this question was the change in velocity '3' or '-3'?

in part c) we had to apply F=ma ... in which we had to change the acceleration to poisitive because force cannot be in negative???

yes you are right !

change in velocity could be either -3 (or) 3
accerelation must be in negative which was - 2308ms^-2 (or) -2307 ms^-2
but when we have to calculate the force then we have to take acceleration positive

 

[Prince III]

hey guys....what was wrong with the last question in SEC B ?
I have read the whole syllabus but didnt found out anything mentioned about RECTIFIERS AND RECTIFYING CIRCUITS...
That why did they gave us to draw in examination?????
I did nothing about that part

NO !
it is mentioned in sylabuss
by the way the correct diagarm was lke this

 

[Mohsin]

Yes the acceleration was supposed to be in negative.. because initial speed was 25m/s and final was 22m/s...
and the time taken was 0.0013s which if u put in the acceleration formula you get -2300m/s .....

but i have 2 questions...

in part a) of this question was the change in velocity '3' or '-3'?

in part c) we had to apply F=ma ... in which we had to change the acceleration to poisitive because force cannot be in negative???

yes you are right !

change in velocity could be either -3 (or) 3
accerelation must be in negative which was - 2308ms^-2 (or) -2307 ms^-2
but when we have to calculate the force then we have to take acceleration positive

i did not put a negative sign with the acceleration
but i wrote the formula correct which is
V-U /t

and my acceleration was + 2308 ms ^ -2


would i be given marks ???

 

[usama1993]

hey guys....what was wrong with the last question in SEC B ?
I have read the whole syllabus but didnt found out anything mentioned about RECTIFIERS AND RECTIFYING CIRCUITS...
That why did they gave us to draw in examination?????
I did nothing about that part

NO !
it is mentioned in sylabuss
by the way the correct diagarm was lke this

hey...i didnt found it in the syllabus....which topic is it mentioned in???

 

[usama1993]

Hey guys...please check this DIAGRAM...
i have drawn it in the first question of SEC B in which the pushing of bus was discussed.
This is the answer of the part which said "USE A GRAPHICAL METHOD TO FIND THE RESULTANT FORCE OF THE WEIGHT OF BUS AND THE PEOPLE'S PUSHING FORCE'="...
Please check it...

 

[Zeuss]

GUYS I GOT THE ACCELERATION IN NEGATIVE ANSWER NOW DO I HAVE TO REMOVE THE NEGATIVE SIGN DURING SUBSITUTION WITH THE FORMULA
F=MA

Yes, ur acceleration supposed to be a negative value. And u should remove the negative sign when using the F=MA formula

 

[Zeuss]

Hey guys...please check this DIAGRAM...
i have drawn it in the first question of SEC B in which the pushing of bus was discussed.
This is the answer of the part which said "USE A GRAPHICAL METHOD TO FIND THE RESULTANT FORCE OF THE WEIGHT OF BUS AND THE PEOPLE'S PUSHING FORCE'="...
Please check it...

First of all its 10 degress.
And the magnitude shud be correct but ur direction is wrong. U shud use the parallelogram method. Complete a parallelogram from the 2 forces and the resultant force is the diagonal from the top left corner to the bottom left corner

 

[Zeuss]

First Question. (Cricket)
Isn't the change in velocity should be 47m/s?
Since they are asking for change in VELOCITY, NOT SPEED.
The ball is moving forward at a speed of 25m/s (velocity = 25m/s)
The ball its hit to the OPPOSITE direction and it travels at the speed of 22m/s (velocity = -22m/s) <=[NEGATIVE]
So the change in velocity = 25m/s - ( - 22m/s)
= 25m/s + 22m/s
= 47m/s

Check the definition of velocity and its difference between speed.

 

[usama1993]

Hey guys...please check this DIAGRAM...
i have drawn it in the first question of SEC B in which the pushing of bus was discussed.
This is the answer of the part which said "USE A GRAPHICAL METHOD TO FIND THE RESULTANT FORCE OF THE WEIGHT OF BUS AND THE PEOPLE'S PUSHING FORCE'="...
Please check it...

First of all its 10 degress.
And the magnitude shud be correct but ur direction is wrong. U shud use the parallelogram method. Complete a parallelogram from the 2 forces and the resultant force is the diagonal from the top left corner to the bottom left corner

so have i done it the wrong way?????????/

 

[Pals_1010]

Yeah i thought that too...

The initial and final speed act in opposite directions...
So one value becomes positive and the other negative.

I got 47 m/s for change in velocity as well...

Since acceleration is CHANGE IN VELOCITY per unit time...

But the value i got is quite large so i wonder...

Anyone got an idea???

 

[Brains]

hey people i rounded the acceleration answer in 2 significant figures as all the values given were in 2 significant figures...

do they cut marks for that????

 

[ALIBABA007]

thanks, but the rectifier was not mention in the syllabus

 

[ALIBABA007]

what was the mass of the ball in the first question ??

 

[bamteck]

The Paper 2 suckx for me !

It was really a tough one compared to the precedent years!!

What about the question 2 in section A?

 

[bamteck]

Do u think the paper 1 & 4 gonna be easy?

I've worked out 18 paper 2 before da exams but still, da paper was tough for me!

 

[Prince III]

Hey guys...please check this DIAGRAM...
i have drawn it in the first question of SEC B in which the pushing of bus was discussed.
This is the answer of the part which said "USE A GRAPHICAL METHOD TO FIND THE RESULTANT FORCE OF THE WEIGHT OF BUS AND THE PEOPLE'S PUSHING FORCE'="...
Please check it...

sorry you have done this wrong
your both direction and resultant would be wrong

you have not looked that the forces were in opposite direction

see the below method

 

[Prince III]

thanks, but the rectifier was not mention in the syllabus

yes it's not mentioned in sylabuss but your teacher should have explained about it as all teachers does explain it !
it is an component whoes function is to convert A.C current into D.C current

Do u think the paper 1 & 4 gonna be easy?

I've worked out 18 paper 2 before da exams but still, da paper was tough for me!

we hope that's easy so that we could grasp more marks in them

hey people i rounded the acceleration answer in 2 significant figures as all the values given were in 2 significant figures...

do they cut marks for that????

yes, your marks would be deducted !!

The Paper 2 suckx for me !

It was really a tough one compared to the precedent years!!

What about the question 2 in section A?

NO doubt !
this was a difficult paper !
most of the candidates found it difficult so percentile would drop hopefully