Physics: Post your doubts here!

[muzzammil13]

IS there WAVES in P4?

 

[Komail Sabba']

Paper 4: Doubt on repetitive question.
Milikan's experiment, where they give you around 5 values of charges on oil droplets and you are required to find the elementary charge.

 

[farhan980]

Can someone please help me with oct nov 2014/43 Q.10/b/ii

 

[TheJDOG]

Can someone please help me with oct nov 2014/43 Q.10/b/ii

Just draw half rectangles with their heights at +5v and -5v since it can never exceed the supply. Each time, draw the half rectangle opposite to the vin , if the cycle of vin is +ve, draw vout at -ve and vice versa

 

[TheJDOG]

Paper 4: Doubt on repetitive question.
Milikan's experiment, where they give you around 5 values of charges on oil droplets and you are required to find the elementary charge.

The elementary charge (1.6 x 10^-19) is a multiple of the differences of the given charges.

 

[mehria]

see question 700 at
http://physics-ref.blogspot.com/2015/05/physics-9702-doubts-help-page-142.html

in p5 r we supposed to extend the best fit line or draw it frm the lower point to the upper point?

 

[Hassan Mirza Aziz]

Can anyone predict or have any idea whats coming in physics p33?

 

[Komail Sabba']

The elementary charge (1.6 x 10^-19) is a multiple of the differences of the given charges.

Is there a specific order to subtract from them?
Like: arrange from largest to smallest and subtract in order
Or: subtract in the given form
Or how?

 

[The Sarcastic Retard]

Use speed of approach and seperation concept.

Ok guys I have a question about momentum.
Assume a scenario where two masses of equal masses and acceleration are moving towards each other about to collide.
Can we predict their behavior after collision. Do they bounce back with same velocity or acceleration? Or stick together and stay stationary? Or is it impossible to predict?

 

[mehria]

extend it

but in s2014 v 51 ths isnt the case... the lower n upper ends are till the plotted points... they r nt extended... :/

 

[mehria]

...
I don't know. If it's from the markscheme, it says the lower end should PASS between ...... In my opinion, if this end at that point, the MS should have said 'the lower end should BE at point ....' + we don't know if the line is exactly at a point, there could be an error at that point?

actually, i haven't yet read much about how the practical papers should be tackled, so I can't help here (can't be 100% sure what to do here).
What did your teacher say about these?

he said nthng abt p 5.. (-_-)

 

[mehria]

...
I don't know. If it's from the markscheme, it says the lower end should PASS between ...... In my opinion, if this end at that point, the MS should have said 'the lower end should BE at point ....' + we don't know if the line is exactly at a point, there could be an error at that point?

actually, i haven't yet read much about how the practical papers should be tackled, so I can't help here (can't be 100% sure what to do here).
What did your teacher say about these?

http://maxpapers.com/wp-content/uploads/2012/11/9702_s13_qp_42.pdf
Q3 (a) (ii) y do we use cos for x?

 

[Debonny1]

How do we know if a sphere is a conductor if a graph of electric field strength against distance from the sphere is given?

 

[buckle_crackk]

A cannon fires a cannonball with initial speed v at angle α to the horizontal.


Which equation is correct for the maximum height H reached?
A H = v sinα / 2g
B H = g sinα / 2v
C H = (v sinα)2 / 2g
D H = g2 sinα / 2v

i found the vertical component = Vsina ...hence, options B and D are ruled out.... but why is the answer C?

 

[Ahmed Aqdam]

A cannon fires a cannonball with initial speed v at angle α to the horizontal.


Which equation is correct for the maximum height H reached?
A H = v sinα / 2g
B H = g sinα / 2v
C H = (v sinα)2 / 2g
D H = g2 sinA / 2v

i found the vertical component = Vsina ...hence, options B and D are ruled out.... but why is the answer C?

Apply 2as=v^2-u^2
a is -g, v is 0 and u is vsinα.
Insert these values to get C.

 

[..sacrifice4Revenge..]

I really need help with this concept:

http://prntscr.com/75vq5i

may june 11 42 q9 b.

how do we identify across which resistor is the input going to be?
for example, in this case. is the 4.5V going to go to the Non-iverting input from across the 1kV resistor or the strain gauge?

A generalised explanation is needed on this thing,not this question specific. since I struggle on every question of this kind.


Thanks a lot and God Bless!

 

[farhan980]

Just draw half rectangles with their heights at +5v and -5v since it can never exceed the supply. Each time, draw the half rectangle opposite to the vin , if the cycle of vin is +ve, draw vout at -ve and vice versa

Thank you very much but what about the width of the rectangle. Im still confused about that.

 

[TheJDOG]

Thank you very much but what about the width of the rectangle. Im still confused about that.

The width depends on where Vin is 0, so everytime the graph of Vin is 0 you switch the polarity try sketching it and upload it here so I check how you sketched it

 

[TheJDOG]

Could someone just give me a quick explanation with tips on how I should find the area under a graph when I'm asked to do so? Do I count the squares? Then what? Thank you

 

[mehria]

check at
http://physics-ref.blogspot.com/2014/07/9702-june-2013-paper-42-worked.html

bcoz at t=0, the displacement is not zero. if you plot a graph, the oscillations would correspond to a cos graph, not a sine.

for sine, when t=0, displacement is also zero


...well, this should also have been in your notes

yea but i was confused ...
thnks..