Physics: Post your doubts here!

[Zepudee]

nop.. it will be a curve with increasing gradient because f is proportional to I^2

HEHE OKAY THANKS! Thanks to Snowysangel

 

[umair1161]

Hello, for Q5 b I,
Anti nodes are the points where there is maximum displacement of the wave, in this case, they're three antinodes.
Nodes are the points where there is zero displacement, in this case, they're 4 nodes, including 2 nodes at P and Q.
For Ii) look at Wave PQ carefully, you'll see that it's 1.5 lambda.
In part a) you already worked out lambda and got that it's 0.8m
So for length of PQ just substitute and you'll get Length= 1.5 x 0.8 = 1.2 m

For part three, look 2 pages back in this thread and you'll see the explanation with an animation.

It is?? Can you please link me the post please! cant find it!

Thanks

 

[marimin]

Smaller radius means smaller force, and hence smaller acceleration.
It will be of the same shape, below the original curve

thanks a lot . I am still confused but. Correct me if i am wrong...doesnt smaller radius means smaller resisting forece...hence smaller deceleration?? and also higher terminal velocity reached....???

 

[AhsanAfzal]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s13_qp_23.pdf
Q6 (c) (ii) explain this
shouldnt pd remain same in parallel and series arrangement across R2when R1 is zero

explain this pls

 

[Browny]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_2.pdf

In question paper 21 can anyone explain Q)5) especially part b)?

 

[papajohn]

Best of all for all those appearing for Physics Paper 2.

 

[_Ahmad]

Hey,
So question 4 (b) (i) is the area between the two lines, because that is the energy lost
For 4 (b) (ii), you need to find the area between the two lines, by counting squares.
Hope that helps.

All the best.

can you please tell me how to find the area by counting square

 

[_Ahmad]

Can anyone "PLEASE" explain Q3 c) from http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_21.pdf

 

[Snowysangel]

When do we take mass as kg and when as grams?

 

[danial 234]

Can anyone "PLEASE" explain Q3 c) from http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_21.pdf

suppose B as pivot... then take distances from it of A and ball... use principle of moments to get the force of A

 

[MiniSacBall]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w09_ms_21.pdf

Q6 b) Idk how to do this .

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_22.pdf
Q4 c)
'at lowest frequency, length = λ/4'

Why can't λ be like λ/6 or λ /8...etc.

 

[forever_chocoholic]

Hello for the ripple tank question 5 c,

They asked us to draw and explain, you need to draw the ripple tank and label, you need to show a light source and label it, and draw a screen and also you need to tell them that you use a video camera to observe the waves.



For 5b, if you look at the wave T1, you'll see that 1 Wavelength is 6 blocks.
We know that 1 Wavelength is 360 degrees.
It's given that T2 lags 60 degrees behind.
So we do, 360---> 6 blocks
60-----> ? Blocks

So this means that t2 lags behind t1 by one block.
When you draw t2 it has to have the same Amplitude A as of T1
Superposition principal : When two waves meet, total displacement is the vector sum of the individual displacements of the waves.

If I have any mistakes someone correct me Good luck on tomorrow's Physics P2 guys

when i drew th wave i got my amplitude as
i)0.5A
ii)-A
iii)-1.5A
my first answer was correct but the other two are wrong according to the mark scheme.. could uplease explain!

 

[AhsanAfzal]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s13_qp_23.pdf
Q6 (c) (ii) explain this

 

[Snowysangel]

explain this pls

The effect resistance will be less in parallel when the resistance in R1 is zero, but for the resistance to be at a minimum in series, R1 should have the greatest possible resistance ie 400 ohms so that the effective resistance if R2 will be relatively less, hence decreasing the pd across it
BTW this was one confusing question

 

[Snowysangel]

if mass cancels out in some way then let it be in grams or else it SHOULD be in kg coz it's the SI unit!

Even in momentum right?

 

[JAVERIA INAM DANISH]

An aircraft travels the first 200m in 6 seconds and the next 200m in 4 seconds. Calculate the initial velocity and the acceleration of aircraft.
Please help!!!!!

 

[Snowysangel]

The effect resistance will be less in parallel when the resistance in R1 is zero, but for the resistance to be at a minimum in series, R1 should have the greatest possible resistance ie 400 ohms so that the effective resistance if R2 will be relatively less, hence decreasing the pd across it
BTW this was one confusing question

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s13_qp_23.pdf
Q6 (c) (ii) explain this

But for the effective resistance to remain constant, the resistance of R2 in parallel has to be greater than than in series

 

[Haya Ahmed]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s13_qp_23.pdf

Q5 b(i) with explaination please

 

[sma786]

"The directory does not exist"-Link mein problem hai?

Um its October November 2010 paper 21.. If you can open it on google please :$ because I am from my cellphone

 

[Haya Ahmed]

ok,remember this sister
always for minimum,phase difference ,it is an odd multiple of pi(pi,3pi.5pi)
and for maximum, it's always an even multiple of pi(2pi,4pi,6pi)
are the answers 1.pi
2.2 pi????????????
the units are radians!

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s13_ms_23.pdf
this is the marking scheme .. the answer is given in the form of formulas or something ! I can't get it