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Reply 80
Original post by omarali1212
I disagree with you mate, I think it will probably be 62 or 63 for an A and like 67 for an A*.


I was talking about mechanics not core 3, because there is no A* in mechanics
Original post by omarali1212
I disagree with you mate, I think it will probably be 62 or 63 for an A and like 67 for an A*.


Mechanics doesn't contribute to an A* (other than getting your 480 UMS). You need an average of 90% on Core 3 and 4. Mechanics is an AS exam.
Reply 82
MathsMechanicsBoat.JPG

This is how I understood the boat question, then used sine rule twice (couldn't remember cosine) to get the speed.

180 - tan^-1 (4/3) = 127
Sin127 / 4 = Sin(theta) / 3
(theta) = 37
180 - 37 - 127 = 16.2
x / Sin16.2 = 3 / Sin 37
x = 1.4 ms^-1
Reply 83
i think this paper will be one of few that has had a cap for 100ums
Original post by Boxed
i think this paper will be one of few that has had a cap for 100ums


What do you mean by this?
Original post by chocolate102030
What do you mean by this?


A 'cap' means that for that paper, to achieve 100 UMS 75/75 raw marks will not be needed. For example getting 73-75 may get you 100 UMS. This happens when examiners feel that the paper was harder than previous years.
Reply 86
what do you guys think 53/75 will be in terms of UMS?
Reply 87
Just thought I’d make an unofficial mark scheme for the MM1B aqa paper. Let me know your opinions on this and whether you agree or disagree :smile: good luck everyone!

1ai) t = 40 seconds (3 marks)
1aii) deceleration = -0.2/0.2 ms-2 (3 marks)
1bi) acceleration = 0.4 ms-2 (3 marks)
1bii) velocity = 40 ms-1 (3 marks)
1c) average speed = 22.4 ms-1 (2 marks)

2a) resultant = 7i + 8j N (2 marks)
2b) magnitude = 10.6 N (2 marks)
2c) acceleration = 2.12 ms-2 (2 marks)
2d) angle = 48.8o (3 marks)

3a) Diagram with R, F and 3g in correct directions (1 marks)
3b) R = 22.5N (2 marks)
3c) Friction = 4.5N (2 marks)
3d) acceleration = 4.80 ms-2 (3 marks)
3e) no air resistance? (1 marks)

4a) R = 520N (3 marks)
4b) tension exerted on trailer = 1280N (3 marks)
4c) tension exerted on the tractor = 1280N (1 marks)

5) 2 possible speeds of B after collision: 1.25 ms-1 or 2.75 ms-1 (6 marks)

6a) show that alpha = 53.1o (2 marks)
6b) magnitude of resultant velocity of boat on return journey = 1.4 ms-1 (6 marks)

7a) expression for v at time t: v = (6i + 2.4j) + (-0.8i + 0.1j)(t) (2 marks)
7b) r = (6i + 2.4j)(t) + (0.5)(-0.8i + 0.1j)(t2) + 13.6i (3 marks)
7c) t = 12seconds, distance travelled = 45.6m (7 marks)

8a) horizontal component = 16 ms-1 (2 marks)
8b) V = 20.6 ms-1 (5 marks)
8c) alpha = 39.1o (3 marks)

I think this may be about right, any comments or changes you think are needed just ask :biggrin:
Original post by MBA007
Just thought I’d make an unofficial mark scheme for the MM1B aqa paper. Let me know your opinions on this and whether you agree or disagree :smile: good luck everyone!


Terrific work on an unofficial mark scheme. Do you happen to have the paper?
Reply 89
Original post by SherlockHolmes
Terrific work on an unofficial mark scheme. Do you happen to have the paper?


Erm I got it off my teacher but he took it back. Sorry :/
What did everyone get on this Mechanics paper?
Reply 91
Original post by SherlockHolmes
What did everyone get on this Mechanics paper?

Erm I got full marks thankfully :smile: guess I got lucky on the day with the questions. Could never do it again though :s how about yourself?
Aaah I was wondering where this thread had gone - couldn't find it! I walked out of the exam almost trembling at the difficulty of it, my answers were all frantic scribbles and scattered with bits crossed out and desperate attempts to scrape by. Absolutely expected a C or D in it. Got an A! :biggrin: Around 85 ums I think.

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(edited 11 years ago)
Original post by MBA007
Erm I got full marks thankfully :smile: guess I got lucky on the day with the questions. Could never do it again though :s how about yourself?


Full marks also :smile: I knew I got the momentum question and another wrong though so must have just been within the cap for 100 UMS.
Reply 94
Has anyone got the paper?
Original post by SherlockHolmes
Trailer
Resistive force = 800N
Mass = 2400Kg

Tractor
Resistive force = R
Mass = 3500Kg

Acceleration = 0.2 ms-2
Driving force = 2500N

First question asked you to work out R which is 520N.
Second question asked you for the tension exerted on the trailer which is 1280N.
Third question asked to state the tension exerted on the tractor which should be equal to the tension exerted on the trailer which is 1280N.

How did u work out the Tractor/Trailer questions?
Original post by brotheromar
How did u work out the Tractor/Trailer questions?


The full question was:
'A tractor, of mass 3500kg, is used to tow a trailer, of mass 2400kg, across a horizontal field. The trailer is connected to the tractor by a horizontal tow bar. As they move, a constant resistive force of 800 newtons acts on the trailer and a constant resistance force of R newtons acts on the tractor. A forward driving force of 2500 newtons acts on the tractor. The trailer and tractor accelerate at 0.2ms-2.

a) Find R.

b) Find the magnitude of the force that the tow bar exerts on the trailer.

c) State the magnitude that the tow bar exerts on the tractor.'

For part (a):

Using F=ma and taking the mass of both the tractor and the trailer,

Driving force - resistive forces = mass x acceleration

2500 - 800 - R = (2400 + 3500) x 0.2

Rearranging for R,

R = 2500 - 800 - (2400 + 3500) x 0.2
R = 520N

For part (b):

Using F=ma but focussing on only the trailer this time,

Forward force - resistive forces = mass x acceleration

T - 800 = 2400 x 0.2

Rearranging for T,

T = 800 + 2400 x 0.2
T = 1280N

For part (c):

The tension exerted by the tow bar on the tractor and trailer must be equal therefore the force exerted by the tow bar on the tractor is also 1280N.
(edited 11 years ago)
Reply 97
Original post by linnet18
Has anyone got the paper?


Hi, if you see my separate thread, you will see that I have posted up all the questions from this paper.
Reply 98
Hey I'm doing the mechanics exam in June. I'm just going through the Jan 2013 paper and i was wondering if someone could explain Q4b and 4c please?
Original post by wasia
Hey I'm doing the mechanics exam in June. I'm just going through the Jan 2013 paper and i was wondering if someone could explain Q4b and 4c please?


Tell us the question?

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