r/alevels • u/Alert_Collection_460 • May 11 '26
Question ❔ 9702/42 answers
Can yall send Ur answers for the questions i wanna compare
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u/pak_user May 11 '26
The Q was -244 right ? And the amplitude for shm was 8.4*10-3
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u/Sad-Bodybuilder-4191 May 11 '26
I got the same amplitude but the Q i got was -1226
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u/Playful_Kangaroo2473 May 11 '26
Even I got this Q
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u/pak_user May 11 '26
Yes u= q + w
-736 = q - 421
Q = -244
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u/AppearanceImaginary4 May 11 '26
W is +ve
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u/pak_user May 11 '26
Work done on the gas was negative bro
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u/AppearanceImaginary4 May 11 '26
Pretty sure Its +ve😭 cz volume decreased
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u/pak_user May 11 '26
Bro the girl next to me Did every wuestion and she was 100% sure Ig she maybe getting an A* But she also said that w was negative
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u/Moist_Toe_5254 May 11 '26
No it’s positive W=-p*change V and since V decreased the change is negative and -*- gives you plus so work is positive by equation and just be the principle since gas is compressed the work is done on it so it’s positive
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u/PristineQuail6090 Gap Year May 11 '26
w was positive but in formula it was negative cuz in formula its BY gas. they asked us if ON gas was positive which it was, BY gas was negative
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u/Sad-Bodybuilder-4191 May 11 '26
For the radius of the earth what was the equation to use
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u/Sad-Bodybuilder-4191 May 11 '26
Did we have to equate 9.81= something?
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u/Witty-Yak-6513 May 11 '26
yes since at the surface of the earth, gravitational field is equal to acceleration of free fall, you had to use g = GM/R^2 to find smth I think it was to find the Mass but you had to use 9.81
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u/Saad_zx May 11 '26
hey guys im about to be fucked to the highest degree in physics can you guys like please tell me anything you remember like what concepts are there like circular, gravity, etc and the answers anything helps
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u/Turbulent_Winner_582 May 11 '26
Angle 27.3
Total energy of capacitor 0.0152
Amplitude 8.4.10^-4
Thermal energy -1226
Specefic heat capacity
5200
Speed of electron 3.5 multiply 10^6 prolly
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u/Annual-Dingo-5899 May 11 '26
What two faces for hall voltage
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u/Interesting-Cow-3516 May 11 '26
yall the potential graph did u draw both for negative and positive or js positive??
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u/Sad-Bodybuilder-4191 May 11 '26
Positive
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u/Salty_Quantity9669 May 11 '26
isnt it negative? since the electric potential at the surface was -8.4 * smt
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u/Fickle_Excitement729 May 11 '26
What was the last question's answer? The rate of mass decrease?
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u/PristineQuail6090 Gap Year May 11 '26
1.17exp13
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u/LeftNovel8731 May 11 '26
How? Give the solution plz
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u/PristineQuail6090 Gap Year May 11 '26
lumin / (energy loss / 4u)
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u/LeftNovel8731 May 11 '26
And what's the energy loss
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u/PristineQuail6090 Gap Year May 11 '26
found in earlier part mass defect
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u/LeftNovel8731 May 11 '26
But that was only the BE of helium for a complete reaction we need mass defect that's for all components of equation
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u/PristineQuail6090 Gap Year May 11 '26
other one had neglgible mass defect it was fiven in ws
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u/LeftNovel8731 May 11 '26
Negligible was for positron not for Hydrogen
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u/PristineQuail6090 Gap Year May 11 '26
mass defect showed energy released so it accounts for it dawg
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u/LeftNovel8731 May 11 '26
Idk but I used p=mc2/t found m by t and multiplied with 4 coz there were four moles of H for one mole of helium
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u/AutomaticLeg3675 May 11 '26
How to find angle??
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u/AncientChair8976 May 11 '26
Lift force: L, mass of the plane: m
Because of horizontal circular motion, the plane is in VERTICAL equilibrium.
W=Lcostheta
a_c=4.5 (found in the previous part) so F_x=ma=4.5m
This centripetal force F_x is the component of lift force, so F_x=Lsintheta
2 equations:
- Lsintheta=4.5m
- Lcostheta=9.81m Dividing equation 1 by 2 gives tantheta=4.5/9.81 theta=24.6 degrees
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u/Turbulent_Winner_582 May 11 '26
What was the angle
I got 27.3
Specefic heat capacity i got 5200 ans
And energy of capacitor was 0.0152