Never really considered the other way and we were taught to use that method in class, I wasn't going to take any risks on the real paper with a method I hadn't tried before.(Original post by Adam998)
Why do that? That's so much extra hassle
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OCR A Physics AS Breadth 24/5/16
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 81
 25052016 07:53

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 82
 25052016 08:11
Yeah I got 79 as well

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 83
 25052016 17:48
(Original post by jn998)
Never really considered the other way and we were taught to use that method in class, I wasn't going to take any risks on the real paper with a method I hadn't tried before. 
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 84
 25052016 19:26
(Original post by teachercol)
Section B
Q21 a) Mass is a scalar; velocity is a vector
Masses add like numbers ; need to take directions into account when adding velocities (2)
b) Tension in string and weight (1)
suvat t = 0.73s (2)
Total : 5
Q22 a) Gradient of graph = 2a
If all points move left or right by same amount (systematic error) then gradient is unchanged (1)
b) Grad = (68012) (45  10) = 2a so a=8.0 ms2 so F = ma = 7360N (3)
Total: 4
Q23 a) Measure diameter in several places with micrometer or vernier callipers.
Calculate A = pi x (dia/2 )^2
Measure weight on scales. (3sf)
Calculate P = weight / area (4)
b) i) (When an object is wholly or partially immersed in a fluid) Upthrust = weight of fluid displaced (1)
ii) Nasty Upthrust = 9.0 7.8 = 1.2N
so mass of water displaced = 1.2 / 9.81
so volume of water = vol of cylinder = 1.2/9.81 / 1000
mass of cylinder = 9.0 / 9.81
so density = mass / volume = 1000 x 9.0 / 1.2 = 7500 kg m3 (3)
Total: 8
Q24 a) N2 Resultant force is equal to the rate of change of momentum of an object (and in the same direction) (1)
b) i) Conserved 2 from mass / momentum / energy / angular momentum not KE (1)
ii) forces are equal and opposite so reflect in x axis (upside down) (2)
c) Perfectly elastic so can use either KE or momentum conservation
500 x 1.7E27 =  420 x 1.7E27 + 2.0E26v
v = 78 ms1 (3)
Total: 7
Q25 a)i ) similarity both energy converted per unit charge / both measured in volts
difference emf is to electrical PD is from electrical (2)
ii) Sneaky n = N / V = 9.6E16 / (1.2E6 x 6.0E3) = 1.33E24
I  nAvq so v = 3.0E3 / (1.33E25 x 1.2E6 x 1.6E19 ) = 1.12E3 ms1 (3)
b) Circuit with cell and variable resistor. Ammeter in series; voltmeter across cell (or R)
Measure terminal PD and current. Very R repeat.
V = E  I r
Plot graph with V on y axis and I on x axis
Gradient = r so r =  gradient (4)
Total: 9
Q26 a) i) 180 out of phase / move in opposite directions (1)
ii) lambda / 2 = 40.0cm + 2.0 cm (5% error)
so v  f x lambda = 75 x 0.40 x 2 = 60 + 3 (also 5% error) (3)
b) i) waves created when release travel to ends and reflect (180 phase shift)
superposition means AN in centre (constructive interference /reinforcement) and nodes at ends (destructive interference /cancellation) (2)
ii) Node to node = lambda /2 so measure length of string
lambda = 2 x length (1)
Total: 7
Q27 a) I is zero so R is infinite
I increases as LED lights so R decreasing
I increases a lot as V increases a little bit so R continues to decrease. (4)
b) cell / LED is wrong way round . LED doesn't turn on until 2.6v+
so reverse cell / LED and add more cells. (3)
c) f = c/ lambda = 3.0E8/480E9 = 6.25E14Hz
E = hf = 4.14E19J
P = E x N so N = 2.9E15 (3)
Total : 10
and there we have it.
I think that's pretty tough. Grade boundaries will be a lot lower than any recent Mech / EWP paper.
Best guess?
A 45
B 40
C 35
D 30
E 25
Could be lower.
Good Luck
ColLast edited by qwertyuiop1998; 25052016 at 19:29. 
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 85
 26052016 09:59
(Original post by qwertyuiop1998)
For Q 27b did you have to put both the LED is in the wrong direction AND the voltage of the circuit is lower than 2.6V? Or did you have to choose one of them to explain? Also how likely is it that it would be 45 for an A? 
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 86
 26052016 12:35
(Original post by qwertyuiop1998)
For Q 27b did you have to put both the LED is in the wrong direction AND the voltage of the circuit is lower than 2.6V? Or did you have to choose one of them to explain? Also how likely is it that it would be 45 for an A?
Tbh we're all just guessing about the boundaries since we don't have any previous papers to go on. 
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 87
 28052016 10:01
(Original post by teachercol)
Section B
Q21 a) Mass is a scalar; velocity is a vector
Masses add like numbers ; need to take directions into account when adding velocities (2)
b) Tension in string and weight (1)
suvat t = 0.73s (2)
Total : 5
Q22 a) Gradient of graph = 2a
If all points move left or right by same amount (systematic error) then gradient is unchanged (1)
b) Grad = (68012) (45  10) = 2a so a=8.0 ms2 so F = ma = 7360N (3)
Total: 4
Q23 a) Measure diameter in several places with micrometer or vernier callipers.
Calculate A = pi x (dia/2 )^2
Measure weight on scales. (3sf)
Calculate P = weight / area (4)
b) i) (When an object is wholly or partially immersed in a fluid) Upthrust = weight of fluid displaced (1)
ii) Nasty Upthrust = 9.0 7.8 = 1.2N
so mass of water displaced = 1.2 / 9.81
so volume of water = vol of cylinder = 1.2/9.81 / 1000
mass of cylinder = 9.0 / 9.81
so density = mass / volume = 1000 x 9.0 / 1.2 = 7500 kg m3 (3)
Total: 8
Q24 a) N2 Resultant force is equal to the rate of change of momentum of an object (and in the same direction) (1)
b) i) Conserved 2 from mass / momentum / energy / angular momentum not KE (1)
ii) forces are equal and opposite so reflect in x axis (upside down) (2)
c) Perfectly elastic so can use either KE or momentum conservation
500 x 1.7E27 =  420 x 1.7E27 + 2.0E26v
v = 78 ms1 (3)
Total: 7
Q25 a)i ) similarity both energy converted per unit charge / both measured in volts
difference emf is to electrical PD is from electrical (2)
ii) Sneaky n = N / V = 9.6E16 / (1.2E6 x 6.0E3) = 1.33E24
I  nAvq so v = 3.0E3 / (1.33E25 x 1.2E6 x 1.6E19 ) = 1.12E3 ms1 (3)
b) Circuit with cell and variable resistor. Ammeter in series; voltmeter across cell (or R)
Measure terminal PD and current. Very R repeat.
V = E  I r
Plot graph with V on y axis and I on x axis
Gradient = r so r =  gradient (4)
Total: 9
Q26 a) i) 180 out of phase / move in opposite directions (1)
ii) lambda / 2 = 40.0cm + 2.0 cm (5% error)
so v  f x lambda = 75 x 0.40 x 2 = 60 + 3 (also 5% error) (3)
b) i) waves created when release travel to ends and reflect (180 phase shift)
superposition means AN in centre (constructive interference /reinforcement) and nodes at ends (destructive interference /cancellation) (2)
ii) Node to node = lambda /2 so measure length of string
lambda = 2 x length (1)
Total: 7
Q27 a) I is zero so R is infinite
I increases as LED lights so R decreasing
I increases a lot as V increases a little bit so R continues to decrease. (4)
b) cell / LED is wrong way round . LED doesn't turn on until 2.6v+
so reverse cell / LED and add more cells. (3)
c) f = c/ lambda = 3.0E8/480E9 = 6.25E14Hz
E = hf = 4.14E19J
P = E x N so N = 2.9E15 (3)
Total : 10
and there we have it.
I think that's pretty tough. Grade boundaries will be a lot lower than any recent Mech / EWP paper.
Best guess?
A 45
B 40
C 35
D 30
E 25
Could be lower.
Good Luck
Col
For question 25 part b, I put the voltmeter across the variable resistor and said something like "we assume that all of the terminal potential difference is across the variable resistor". Would I lose marks as I didn't put the voltmeter across the cell?
Would much appreciate your help with this 
 Follow
 88
 29052016 08:50
I would also add that for 27 some calculations would be required for R at two different regions to show that it decreases.

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 89
 29052016 08:55
(Original post by mbb123mbb)
Thank you!
For question 25 part b, I put the voltmeter across the variable resistor and said something like "we assume that all of the terminal potential difference is across the variable resistor". Would I lose marks as I didn't put the voltmeter across the cell?
Would much appreciate your help with this 
 Follow
 90
 03062016 18:14
Hey, i think i got like 58/70 what kind of ums i s that

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 91
 04062016 22:03
(Original post by lanteacher)
Voltmeter can go on either (since we are assuming there is no potential difference across wires) so you would be ok. 
 Follow
 92
 06062016 07:09
(Original post by Stormforge9)
Hey, i think i got like 58/70 what kind of ums i s that 
 Follow
 93
 07062016 17:09
anyone got a list of things that wasnt on the breadth paper?

 Follow
 94
 08062016 18:44
(Original post by teachercol)
Section B
Q21 a) Mass is a scalar; velocity is a vector
Masses add like numbers ; need to take directions into account when adding velocities (2)
b) Tension in string and weight (1)
suvat t = 0.73s (2)
Total : 5
Q22 a) Gradient of graph = 2a
If all points move left or right by same amount (systematic error) then gradient is unchanged (1)
b) Grad = (68012) (45  10) = 2a so a=8.0 ms2 so F = ma = 7360N (3)
Total: 4
Q23 a) Measure diameter in several places with micrometer or vernier callipers.
Calculate A = pi x (dia/2 )^2
Measure weight on scales. (3sf)
Calculate P = weight / area (4)
b) i) (When an object is wholly or partially immersed in a fluid) Upthrust = weight of fluid displaced (1)
ii) Nasty Upthrust = 9.0 7.8 = 1.2N
so mass of water displaced = 1.2 / 9.81
so volume of water = vol of cylinder = 1.2/9.81 / 1000
mass of cylinder = 9.0 / 9.81
so density = mass / volume = 1000 x 9.0 / 1.2 = 7500 kg m3 (3)
Total: 8
Q24 a) N2 Resultant force is equal to the rate of change of momentum of an object (and in the same direction) (1)
b) i) Conserved 2 from mass / momentum / energy / angular momentum not KE (1)
ii) forces are equal and opposite so reflect in x axis (upside down) (2)
c) Perfectly elastic so can use either KE or momentum conservation
500 x 1.7E27 =  420 x 1.7E27 + 2.0E26v
v = 78 ms1 (3)
Total: 7
Q25 a)i ) similarity both energy converted per unit charge / both measured in volts
difference emf is to electrical PD is from electrical (2)
ii) Sneaky n = N / V = 9.6E16 / (1.2E6 x 6.0E3) = 1.33E24
I  nAvq so v = 3.0E3 / (1.33E25 x 1.2E6 x 1.6E19 ) = 1.12E3 ms1 (3)
b) Circuit with cell and variable resistor. Ammeter in series; voltmeter across cell (or R)
Measure terminal PD and current. Very R repeat.
V = E  I r
Plot graph with V on y axis and I on x axis
Gradient = r so r =  gradient (4)
Total: 9
Q26 a) i) 180 out of phase / move in opposite directions (1)
ii) lambda / 2 = 40.0cm + 2.0 cm (5% error)
so v  f x lambda = 75 x 0.40 x 2 = 60 + 3 (also 5% error) (3)
b) i) waves created when release travel to ends and reflect (180 phase shift)
superposition means AN in centre (constructive interference /reinforcement) and nodes at ends (destructive interference /cancellation) (2)
ii) Node to node = lambda /2 so measure length of string
lambda = 2 x length (1)
Total: 7
Q27 a) I is zero so R is infinite
I increases as LED lights so R decreasing
I increases a lot as V increases a little bit so R continues to decrease. (4)
b) cell / LED is wrong way round . LED doesn't turn on until 2.6v+
so reverse cell / LED and add more cells. (3)
c) f = c/ lambda = 3.0E8/480E9 = 6.25E14Hz
E = hf = 4.14E19J
P = E x N so N = 2.9E15 (3)
Total : 10
and there we have it.
I think that's pretty tough. Grade boundaries will be a lot lower than any recent Mech / EWP paper.
Best guess?
A 45
B 40
C 35
D 30
E 25
Could be lower.
Good Luck
Col 
 Follow
 95
 10062016 09:35
(Original post by mightyned)
I know this is late but i just wanted to restore some hope for the second exam.for q23bii i got 7519kgm3 using the method1.2/9.8= 0.122volume = mass/density so 0.122/1000 = 0.0001229/9.8= 0.92density= mass/volume 0.92/0.000122= 7519 would i still get all 3 marks even though it was not exactly 7500?
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Updated: June 10, 2016
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