how was physics paper 12? (no discussions till 24 hours)

[I don't care]

hello people i gave C for the ball that was thrown up and moved left. My logic was that the ball was thrown in a parabolic kind of motion to the left. There was no resistive force acting on it so yea the answer was an arrow pointing down and left

 

[DumbIdiot]

hello people i gave C for the ball that was thrown up and moved left. My logic was that the ball was thrown in a parabolic kind of motion to the left. There was no resistive force acting on it so yea the answer was an arrow pointing down and left

why left? once thrown, there was no force acting to the left on the ball. the answer is either only one arrow pointing downwards or two arrows pointing down and left

 

[I don't care]

why left? once thrown, there was no force acting to the left on the ball. the answer is either only one arrow pointing downwards or two arrows pointing down and left

the question said it went up and moved left meaning a projectile motion that's why i gave C.

 

[Muhammad Haris Ghani]

I guess the bangalis are done with their exams :/
I gave an answer which was *directly downwards*
The ball thrown upwards and moved left, woh wala swal..exact answer kisiko pta h?

It was definitely only downwards arrow because at the top only the downwards acceleration is active while horizontal is zero plus velocity constant and in the question force was asked as while acc is active downwards surely gravitational force would be there only air resistance wasnt mentioned...OK

 

[Muhammad Haris Ghani]

why left? once thrown, there was no force acting to the left on the ball. the answer is either only one arrow pointing downwards or two arrows pointing down and left

yes the downwards arrow was the answer and what was your answer for that diffracting grating one that angle formula one?

 

[Moi]

yes the downwards arrow was the answer and what was your answer for that diffracting grating one that angle formula one?

I am very sure the answer was

Sin^-1 (wavelength / D)

I dont think that its 2sin like many said coz it was not a diffraction grating nor the diffraction grating formula...
It was simply A normal diffraction slit

 

[Muhammad Haris Ghani]

I am very sure the answer was

Sin^-1 (wavelength / D)

I dont think that its 2sin like many said coz it was not a diffraction grating nor the diffraction grating formula...
It was simply A normal diffraction slit

and your answer for that partical one

 

[Moi]

and your answer for that partical one

You mean the alpha particles question? Their work done?
I dont remember my answer, maybe if you refresh my memory and tell me the choices?
But I believe it was quiet an easy question which is weird for a person who got a C in physics
If am not wrong... was there a 5x 10^13 ?

 

[Namehere]

Does anyone know what was the answer for the question of the ruler which rotated? The question was, if I remember right something like... At the instant when the rule is horizontal what is the resultant turning moment about the pivot?
Thanks.

 

[Sherko]

Does anyone know what was the answer for the question of the ruler which rotated? The question was, if I remember right something like... At the instant when the rule is horizontal what is the resultant turning moment about the pivot?
Thanks.

I think it should be zero for the rule to be horizontal!

 

[I don't care]

The diffraction grating question's answer was 2sin^-1 (wavelength/D) ... and i got 5* 10^-11 for that alpha particle question... The power station question i got 1.5MJ don't know how but i did... well these are my answers

 

[Hassan Ali Abid]

Does anyone know what was the answer for the question of the ruler which rotated? The question was, if I remember right something like... At the instant when the rule is horizontal what is the resultant turning moment about the pivot?
Thanks.

resultant moment was calculated by subtracting the moment caused by the load - the moment caused by the weight of the ruler...
only then the sum of clockwise moment gets equal to sum of anticlockwise moment

 

[Hassan Ali Abid]

I am very sure the answer was

Sin^-1 (wavelength / D)

I dont think that its 2sin like many said coz it was not a diffraction grating nor the diffraction grating formula...
It was simply A normal diffraction slit

the ans was D for that part ..ie 2sin-(lamda/D) ....i dont remember for the question but im sure i was D bcz i calculated and it was like 2sin-(lamda/D)

 

[Hassan Ali Abid]

what was the ans of the question asking about the gravitional field on the man when he is moving with the acc of 0.2g ????
the ans was 1.2g or just mg ?????

 

[Moi]

the ans was D for that part ..ie 2sin-(lamda/D) ....i dont remember for the question but im sure i was D bcz i calculated and it was like 2sin-(lamda/D)

On what bases is it 2sin-? Its not a diffraction grating so why are u doubling the angle?

 

[Moi]

I think it should be zero for the rule to be horizontal!

It was 1.4 n... clockwise moment minus anti-clockwise moment... the question was... what is the total turning moment. As far as I rremember.

 

[Hassan Ali Abid]

On what bases is it 2sin-? Its not a diffraction grating so why are u doubling the angle?

it was the diffraction grating .....
i cant remember the wording of question but the ans was D :/

 

[Namehere]

W

resultant moment was calculated by subtracting the moment caused by the load - the moment caused by the weight of the ruler...
only then the sum of clockwise moment gets equal to sum of anticlockwise moment

Why can´t it be zero, I mean, the question asked what is the RESULTANT moment at the INSTANT when the rule is HORIZONTAL.

 

[Hassan Ali Abid]

W


Why can´t it be zero, I mean, the question asked what is the RESULTANT moment at the INSTANT when the rule is HORIZONTAL.

it it was zero then the resultant moment cant be zero and the ruler cant be in equilibrium

 

[I don't care]

I am very sure the answer was

Sin^-1 (wavelength / D)

I dont think that its 2sin like many said coz it was not a diffraction grating nor the diffraction grating formula...
It was simply A normal diffraction slit

There were two first orders one above zero order and one below... if you use the formula sin^-1 (wavelength/D) you would find the angle between the zero order and 1st order only.. But the question wanted the angle between the two first orders so you need to multiply by 2