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Physics: Post your doubts here!
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LAST TIME ANSWERING
The question states that "X is measured with a percentage uncertainty of ±1 % of its value at all temperatures." meaning that the percentage uncertainty is unchanged, so A and B is eliminated.
then you need to apply some logic here, will the actual uncertainty get bigger as you approach 100 or 0?.
you can quickly do some math here, 100x1% = ±1 uncertainty while 0x1% = 0
so answer is C, least actual uncertainty when temperature close to 0
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s12_qp_12.pdf
Can anyonne help me with this? Question 7,i don't understand why the answer is A..
Can anyonne help me with this? Question 7,i don't understand why the answer is A..
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JUN 11 P12 Qs ( 4 , 6 , 10 , 13( why isnt it A) , 14 (why not C))
Please help , my concepts are really weak :/
Please help , my concepts are really weak :/
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Will u pls send me the link??? I will solve it den
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s13_12
7)
Total speed will be 10 + 50
so s = (v -(-u)) / 2 * t
so s = 60/2 * 2 = 600m
9)
Mass of wind coming in contact with the blades per second = density * speed * area = 475.2 kg/s
F = mv-mu/t As it is 475.2 kg/s, we will use
F = 475.2*0 - 475.2*33/1 = D
20)
https://www.xtremepapers.com/community/threads/physics-post-your-doubts-here.9860/page-523#post-820191
23)
29)
Use dsinθ = nλ
from first info find d
Then again use that formula and find θ when n is 2
After that subtract it from 15.4 degree you'll get C as the answer
32)
R = ρL / A
R = (1.7 x 10⁻⁸) * (2000) / (Π x (r₂ x 12))
R = 14Ω
33)
First of all we need to find lost volts for power
so V = E - Ir Where V is lost volts, E = e.m.f, I is the current, r is the internal resistance..
I = E/(R + r)
so V = 20 - (2.5 x 1.5) = 16.25V
Now P = IV
so P = 2.5 x 16.25 ≈ 41W
36)
R = V/I
so if R decrease so V will decrease and if R increases so V will increase..
Here, Vp is decreasing as R is decreasing from 10 to zero
And in Vq the R is increasing as R across Vp is decreasing so Vq will decrease.
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14)
moment = force x distance
clockwise moment = anticlockwise moment
W x a + F x h = W x 2a
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15)
for a couple, there has to be two equal forces acting in opposite directions. A is wrong because the forces are acting in the same direction. D is wrong because the forces are not acting in opposite directions. then why is C wrong? right? well C is wrong because two forces are in opposite directions but they are working from the same point. why is this a problem then? torque gives rise to a motion that is circular. so if two equal forces are acting from the same point, the meter rule will not rotate. the meter will stationary. try imagining this picture.
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5)
sagar's edit
Okay, so what we need to find out is the percentage uncertainty in the value of the volume of the sphere with a radius measurement of r = 5.00 mm ± 0.01 mm.
The formula for volume of a sphere as a function of radius is 4πr³/3. Therefore, we are multiplying r into r into r to get r³, and this is the only value in the equation that has any uncertainty - there is no uncertainty in 4/3 and there is no uncertainty in π, so r is the only quantity we need to concern ourselves with.
The rule for uncertainties when any number of quantities are multiplied goes as follows:
"When one multiplies or divides several measurements together, one can often determine the fractional (or percentage) uncertainty in the final result simply by adding the uncertainties in the several quantities."
Let's do this by example. We are multiplying r by itself three times (to get r³) and so to get the percentage uncertainty in the final result, we resort to "adding the uncertainties in he several quantities". In other words, we add the (percentage uncertainty in r) to the (percentage uncertainty in r) to the
(percentage uncertainty in r).
Basically we multiply the percentage uncertainty in r by 3.
The percentage uncertainty in r = (0.01 mm/5.00 mm) * 100 = 0.2 %.
Multiplying this by 3, we get the uncertainty in the volume of the sphere with this radius to be 0.2 * 3 = 0.6% = C.
(more information here: http://spiff.rit.edu/classes/phys273/uncert/uncert.html)
37)
-->After voltage passes through some resistance it will decrease
-->The higher the resistance the greater the decrease in voltage
-->So it will decrease less after passing through 2 ohm than when passing through 4 ohm
38)
Here we are asked to find total EMF in the circuit.
We'll use the formula : EMF*(R1/R1+R2+R3) = V
Now we wont consider 4R coz its parallel attached to other 3 resistors, hence --> EMF*(2/6) =2 so EMF = 6V
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can u also help me with JUN 11 P12 Qs ( 4 , 6 , 10 , 13( why isnt it A) , 14 (why not C))
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http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s06_qp_1.pdf
Q 9
can anyone explain what is the difference between B and D and why the answer is not C .. inshort explain all !! Thanks in advance
Q 9
can anyone explain what is the difference between B and D and why the answer is not C .. inshort explain all !! Thanks in advance
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4) using metre rule with mm divisions , using light gates, using balance which measures to nearest gram .. will increase the accuracy of reading... hence less uncertainty
5) horizontal distance = vt
vertical = 1/2gt^2 (using 2nd eq of motion)
horizontal/vertical= 2v/gt
10) acceleration and force will be in same direction
newtons second law states that" .... resultant force produces an acceleration in the direction of force..."
when velocity is zero, particle is either at its highest piont or at its lowest point. at B the particle is at highest point and at D particle is at lowest pointhttp://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s06_qp_1.pdf
Q 9
can anyone explain what is the difference between B and D and why the answer is not C .. inshort explain all !! Thanks in advance
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13) if we choose A
k.e wont be conserved
initial k.e = 1/2mv^2
final= 1/2m(0.5v^2) + 1/2m(0.5v^2)
= 1/4mv^2
14) the only force acting is gravity.. no air resistance because it is in vacuum .. so force will be in XV only
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in question 6 , isnt the equation of 2nd motion s=ut+0.5at^2
how exactyl did u get the vertical??
also thanks anyways
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i didnt get question (14)
can u explain it again??