Physics paper 2 2015

[AbdullahBShakeel]

DAMN IT.. I thought of the ball at top at 1.25 s but then i changed my mind. Faaaaa :|

 

[iwillrise]

Hey lads, were there any other Qs you found difficult, apart from that q2 monster

 

[AbdullahBShakeel]

Guys i used the Kirchoff's second law for the Resistance of X and i showed them the whole long loop.. But during exam i got a different answer and at home i got 4500. My signs and the loop is on point so i do get 2 marks out of 3 right?

 

[Faiqa Nadeem]

For that one I got 4600 ohms, anyone else?

 

[Faiqa Nadeem]

What about the kinetic model thing for pressure, what were we supposed to write for three marks? And the question where we had to make the normal reaction of the wall on the rod, where was the arrow supposed to be?

 

[AbdullahBShakeel]

What about the kinetic model thing for pressure, what were we supposed to write for three marks? And the question where we had to make the normal reaction of the wall on the rod, where was the arrow supposed to be?

Arrow was on the right.. and right side direction..

 

[asadalam]

What about the kinetic model thing for pressure, what were we supposed to write for three marks? And the question where we had to make the normal reaction of the wall on the rod, where was the arrow supposed to be?

Many gas particles in the gas,show random motion and collide with surface.As they collide their momentum changes.Force is rate of change of momentum so force is exerted.Huge amount of particles so sufficient force exerted on walls.And i drew the arrow horizontally to the right,dunno if its right or not.

 

[Hassan Mirza Aziz]

What do you think will be the gt?

 

[Faiqa Nadeem]

I drew it horizontally to the right as well but someone was saying we had to draw another line from P to where it intersected with weight
The gt for p2 is usually 40 or 39 but idk about this

 

[Llama2617]

Will u get a mark of u write gas molecules collide elastically

 

[Choi WW]

Yo, guys... For the resistance, did they state in the question for giving the answer to 2 sf? Because most of people are saying that it's 4500.. I wrote 4510..

 

[Ahmed Aqdam]

Yo, guys... For the resistance, did they state in the question for giving the answer to 2 sf? Because most of people are saying that it's 4500.. I wrote 4510..

How'd you get 4510? It was 4500 exact. Total resistance was 15000*12/8=22500. So the resistance of the component which had to be found was 22500-(15000+3000)=4500

 

[Choi WW]

How'd you get 4510? It was 4500 exact. Total resistance was 15000*12/8=22500. So the resistance of the component which had to be found was 22500-(15000+3000)=4500

I did like 5.33x10^-4(Rx + 15000+ 3000) =12

 

[Ahmed Aqdam]

I did like 5.33x10^-4(Rx + 15000+ 3000) =12

This method is correct too but its better to take exact value when using answers of previous parts.

 

[AbdullahBShakeel]

I did like 5.33x10^-4(Rx + 15000+ 3000) =12

YUPP I did it like that too! Just that my answer was wrong but thats what i did.. I am sure I get 2 marks for that. In your case you get 3.

 

[Choi WW]

This method is correct too but its better to take exact value when using answers of previous parts.

They won't penalise it write?

 

[Choi WW]

YUPP I did it like that too! Just that my answer was wrong but thats what i did.. I am sure I get 2 marks for that. In your case you get 3.

out of 3??

 

[Ahmed Aqdam]

They won't penalise it write?

Most probably no.

 

[AbdullahBShakeel]

out of 3??

Yes because Kirchoffs law is applicable in any circuit always