Physics: Post your doubts here!

[Zepudee]

Volume = length * width * height
length * width = Area = A
So Volume = A * height or A * h

Ah ah i see, hahaha thanks thanks

 

[ShreeyaBeatz]

This is of paper 5
when we throw a magnet in a vertical coil , how to make the speed uniform in all parts of its vertical motion? The markscheme says -
1.Use of short magnet so that v is (nearly) constant
2. Use short/thin coil so that v is (nearly) constant
WHY? HOW?

 

[Champ101]

Yeah, that should be it. There is an alternate method, though, just in case you're interested:

Find the gradients of the steepest line that passes through all the error bars, and the shallowest line that passes through all the error bars.

Suppose they happen to be 5.7 and 4.3 in any units (and the gradient of the best fit is 4.0).

The calculation you carry out = 0.5 * (Gradient of Steepest line - Gradient of shallowest line)

In our example, this is 0.5 * (1.4) = 0.7 (in the relevant units).
So we'll write that the gradient is 4.0 ± 0.7.

The marking scheme from a 2012 October/November paper probably puts this best:

"Uncertainties in Question 2

(c) (iii) Gradient [U2]

Uncertainty = gradient of line of best fit – gradient of worst acceptable line

Uncertainty = ½ (steepest worst line gradient – shallowest worst line gradient)"

So really, either method is accepted as long as you make it clear which one you are using.

Good Luck with all your exams!

thanks a lot man!!!

 

[Jinosupreme]

PAPER5 doubts,
So for question 2, we obtained gradient and y-intercept, the questions after that, are we suppose to use raw gradient and y-intercept in calculations, or the round up gradient and y-intercept? Thanks guys!

 

[Snowysangel]

Which formula could be correct for the speed v of the ocean waves in terms of the density p of sea water, the acceleration of free fall g, the depth of the ocean h and the wavelength, lambda?

This is from paper 1...and the answer is v=underoot (g x lambda)...but HOW?

 

[ShreeyaBeatz]

PAPER5 doubts,
So for question 2, we obtained gradient and y-intercept, the questions after that, are we suppose to use raw gradient and y-intercept in calculations, or the round up gradient and y-intercept? Thanks guys!

Always use raw
And please do help with my question! thanks

 

[ShreeyaBeatz]

PAPER5 doubts,
So for question 2, we obtained gradient and y-intercept, the questions after that, are we suppose to use raw gradient and y-intercept in calculations, or the round up gradient and y-intercept? Thanks guys!

This is of paper 5
when we throw a magnet in a vertical coil , how to make the speed uniform in all parts of its vertical motion? The markscheme says -
1.Use of short magnet so that v is (nearly) constant
2. Use short/thin coil so that v is (nearly) constant
WHY? HOW?

 

[Mohammed salik]

This is from paper 1...and the answer is v=underoot (g x lambda)...but HOW?

If u Convert Quantities into Base Units.. The Check If Right Hand Side Equals LEFT hand Side..! If it does then Equation is true And Valid..! If u Couldn't The I would Explain Further !
Hope i Helped !

 

[Zain Javaid]

guys what are the formulas for calculating uncertainities in the table of Question 2 P5, and please help with the rest relative information too so that i must hav any problem solving those question. gradient uncertainities always go wrong

 

[A star]

what is the word POT mean i am sick of seeing this in every paper

 

[scouserlfc]

what is the word POT mean i am sick of seeing this in every paper

POT is actually power of ten error.

What does FOX mean any idea I've seen that as well in P5 ms ??.

 

[A star]

POT is actually power of ten error.

What does FOX mean any idea I've seen that as well in P5 ms ??.

meaning???

 

[A star]

This is of paper 5
when we throw a magnet in a vertical coil , how to make the speed uniform in all parts of its vertical motion? The markscheme says -
1.Use of short magnet so that v is (nearly) constant
2. Use short/thin coil so that v is (nearly) constant
WHY? HOW?

so that magnetic field lines are evenly spread out

 

[Zepudee]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s10_qp_12.pdf

Q4,5,28,29,34,37,40!! HEHEHEE

 

[scouserlfc]

meaning???

Are u asking me what FOX means then I have no idea either it's pretty annoying it normally in ms is in the answer for y intercepts so I guess it's ant using false origin axes like they don't use origin on graph for at least x axis and u read the graph at this point thinking it's the y intercept so then u do FOX error I guess.

For POT error it's like when u have to calculate gradients and those sly CIE people have put the unit for an axis as let's say on the x axis they put mass/10^-6 kg. and in gradient calculation u forget this and don't include 10^-6 then u have done POT error and normally they do allow ecf for both POT and FOX but in some cases they don't.

 

[scouserlfc]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_12.pdf

Q4,5,28,29,34,37,40!! HEHEHEE

Don't have time will help with 4 .
Just use SI units of the axes.
Power x time
Js^-1 * s
J = joules
There is only one answer for energy so it's A.

 

[psychiatrist]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s05_qp_1.pdf
Q7,9,20,22,24,25,27,33.... Please

 

[roxy roro]

can someone help me please ? paper5 physics A2 ... if a = 6.6 x 10^-2 ± 0.1 and a^2 = 44 x 10 ^-4 how do we calculate the absolute uncertainty in a^2 ?? it is paper 52 may june 2013

 

[Zain Javaid]

table me uncertainities nikalnay ka kia formula hai ?

 

[roxy roro]

table me uncertainities nikalnay ka kia formula hai ?

what ?!