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AS Physics P1 MCQs Preparation Thread.

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F = kx
First we'll set a comparable value of the extension.
That is, we'll find extension for ONE Load acting on ONE spring.
Let load be W, extension be e.
W = ke,
k = W/e
k is spring constant.

Now we'll find all extensions for the choices in terms of e.

A: Two springs: One load.
W divided equally so each spring takes W/2.
F = kx,
So: W/2 = W/e * x,
x = W/2 *e/W
x = 0.5 e

B: Same set-up as in A. Except the two-spring has another two-spring attached to it.
We'll double the extension. (In series u double ext.)
x = e

C: One single-spring attached to a double-spring set-up.
Single spring will take the whole of load W.
Initially, if u refer to the starting of this reply, u'll see the extension is: e, for a load of W. (That is when the spring takes the whole of the load!)
So for single-spring: ext. is e.
For double-spring set-up, well - just look at A.
x was 0.5 e...
Total ext. for C is: e + 0.5e = 1.5e

D: Single-spring, again, will have ext. e. (Like I said above.)
Triple spring. Each spring takes W/3 load.
F = kx.
W/3 = W/e * x,
x = W/3 * e/W,
x = e/3.

Total ext. for D: e/3 + e = 4e/3 or 1.33e

Compare 'em all.

C has gr8est ext. C's ur answer.

Hope I was of assistance!
 
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Okay so this problem is like parallel and series circuit. just imagine extension as resistors, and if you want overall k then find inverse of overall x. or otherwise the otherway if parallel then k would all add up for overall k. You do it yourself now and see if you got correct
Hey, can u elaborate some more on this method?
 
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Hey, can u elaborate some more on this method?

If a spring is in parallel won't they be more stiff? usually they give identical spring so it is easier, so if 2 springs on parallel their stiffness doubles and the extension just inverse it so 1/2 x, it is the opposite for series where you add the all the x and find inverse of k ;)
 
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If a spring is in parallel won't they be more stiff? usually they give identical spring so it is easier, so if 2 springs on parallel their stiffness doubles and the extension just inverse it so 1/2 x, it is the opposite for series where you add the all the x and find inverse of k ;)
Hmmm... I got it now.
Thanxx.

How's the prep going?
 
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guys i saw some statments regarding energy and mass laws....
can some one guide me plss
it was like this
THE FIRST NEWTONS LAW IS A CONSEQUENCE OF SECOND LAW ....
what about conservation of energy or mass ....they are the consequence of what ???
Conservation of linear momentum is a consequence of what ????
 
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Preps fine just momentum is a bit confusing when it comes to sign and directions. I don't do yearly I do it chapter by chapter. How about you?

It's fine-ish. Have to go over the syllabus once though.
Yeah = momentum gets me too. And that's clever.
Have u done the frequencies nd wavelengths of the waves in the electromagnetic spectrum? I mean, learnt them?
CTRL + Q to Enable/Disable GoPhoto.it
 
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It's fine-ish. Have to go over the syllabus once though.
Yeah = momentum gets me too. And that's clever.
Have u done the frequencies nd wavelengths of the waves in the electromagnetic spectrum? I mean, learnt them?
CTRL + Q to Enable/Disable GoPhoto.it

Yeah man can you post em up ....i need it too!!
 
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Dude here ya go:

Yeah man can you post em up ....i need it too!!

WAVELENGTHS (m)



Gamma Rays 10^-12

X-Rays 10^-10

UV Rays 10^-8

Visible Light 5 x 10^-7

Infra Red 10^-5

Microwaves 1mm ---> 10^3

Radiowaves 10^-3 -----> 1Km


All these waves will have same speed... so just put in v=f lamida to get the frequencies.
 
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The uncertainty (accuracy) in this result is 3%
First calculate it: It's 9.8298
U must remmbr that uncertainties are ALWAYS written correct to 1 SF!
So, the above correct to 1 SF is:
10
Uncertainty will be 10 m/s
Also, remmbr that the calculated answer (speed 327.66 u have), is DEPENDENT on the uncertainty.
I mean that the decimal places (or accuracy in this case) of the speed is determined by the uncertainty.
Uncertainty (accuracy - and let's refer them to be the same thing here for now), is 10.
So speed will be correct to 10m/s

ie 330m/s

That is all.
SO:
Find uncertainty first.
Make it correct to 1 sf
Write calculated value correct to the uncertainty.

eg:
X = 34.5444 m
Uncertainty = 0.00498 m
Make uncertainty 1sf = 0.005m
Write X correct to the uncertainty ie 3dp
X = (34.544 +/- 0.005) m

Tadaa
 
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In q 17 simply use P=Fv.
In q 31:the resistance of each wire wll be 4 ohm.using V=IR calculate resistance for relay that comes 26.67.total resistance will become26.67+8=34.67ohm.multiply it with the current and u will get the voltage.
In Q 13 weight always acts downwards.
dont know q2.
THX but the answer to 17 is A not D so it's showin the opposite:S
 
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