AQA MM1B - Mechanics 1 2016 [Unofficial Mark Scheme] - Tuesday 21st June

hi i was wondering if you'd have a guess about how many marks i'd get for question 6?? i messed up and wrote a '-' sign instead of '+' for the first bit, which obviously carried through to the second part but im confident the rest of my working was completely correct? thanks

June 14 had a similar question
M1: Equation of motion withcorrect terms. Allow sign errors.
A1: Correct equation. May be in terms of m and g.
dM1: Substituting for F using= µRF , where R is in the form+ bXa where a and b are nonzeroconstants.
dM1: Solving for X.
A1: Correct value for X.

Lose probably a mark?

Please let me know if marks are wrong & if any answers are wrong.
I'm missing some marks I think.
Full UMS ~ drop 8 marks ~67/75 ?
Similar or slightly lower than June 2014 imo.

Q1 - Momentum
(a) 0.4 m/s [3 marks]
Particles coalesced, calculate V
(b) m=15 kg [5 marks]
Coalesced particle coalesced with another particle of mass m

Q2 - Force
(a) Resultant force = (p-4)i + (q+12)j [1 mark]
(b) Values p & q: p=14, q=-17 [2 marks]
(c) Distance = 17.9m [3 marks]

Q3 - Toy car
(a) Acceleration = 1.5 ms^-2 [2 marks]
(b) Velocity = 1.8 m/s [2 marks]
(c) Angle of slope = 8.80 ~ 9 degrees [4 marks]
mgsintheta=ma
mgsintheta=m(1.5)
gsintheta=1.5

Q4 - Resultant velocity
(a) 240m due East at t=20 so
V=12 m/s [2 mark]
(b) Resultant velocity = 90.8 m/s [2 marks]
(c) Bearing = 008 degrees [4 marks]

Q5 - Connected particles
(a) Show that acceleration = 3.92 m/s [5 marks]
(b) Velocity of the particle when it hits the ground = 2.50 m/s [2 marks]
(c) String becomes slack when particle moves 80cm, calculate the maximum height of the other particle = 1.12 m [3 marks]

Q6 - Force T applied to block
(a) Find R in terms of T: R = 5g + Tcos60 [3 marks]
(b) Find the Tension = 43.8 N [6 marks]

Q7 - Projectile
(a) Time taken = 1.76s [5 marks]
(b) Distance = 13.6m [2 marks]
(c) Calculate V when angle remains unchanged = 13.2 m/s [7 marks]

Horizontal: 16.6 = Vcos50t
Sub in either V or t into
Vertical displacement 1=Vsin50t - 4.9t^2
To get a value of t=1.96s
Sub into Horizontal equation to find V= 13.2 m/s

(d) Assumption to why the football is modelled as a particle? [1 mark]
Possibility of rotation
Other possible answers?

Q8 - Vectors [10 marks]
A has an initial velocity 8i+4j and acceleration -0.2i+0.1j, at origin.
B has an initial velocity 6i+9j and acceleration 0.2i-0.1j, initial position vector 40i+50j.
Find the distance between A & B at the instant when velocities are parallel.
Distance = 106 m using t=12

Allocation of marks (this is just my guess)
- Write down displacement vectors in terms of t for both A & B (1 marks)
- Write down velocity vectors in terms of t for both A & B (1 marks)
- Finding values of t using velocity vectors and subbing into displacement vectors (6 marks)
- Subtracting displacements (B-A) to get a final displacement vector & calculate distance by using Pythagoras (2 marks)

I think calculating the wrong value of t would lose 6 marks imo.
There are different ways of doing Q8 I'm sure.

*What UMS score do you think I will get if i lose between 14-17 raw marks inclusive from the total 75 raw marks

(oh and by the way question 8 was a shambles... Apparently you had to know about scalar vectors and whatnot ... This question accounted for about half the raw marks i lost)

58-61 marks out of 75 should be roughly 86-92 UMS?
I've got Q8 wrong lol but still hoping for full/near full if I haven't messed up too much on little things like nearest degree etc.

Please let me know if marks are wrong & if any answers are wrong.
I'm missing some marks I think.
Full UMS ~ drop 8 marks ~67/75 ?
Similar or slightly lower than June 2014 imo.

Q1 - Momentum
(a) 0.4 m/s [3 marks]
Particles coalesced, calculate V
(b) m=15 kg [5 marks]
Coalesced particle coalesced with another particle of mass m

Q2 - Force
(a) Resultant force = (p-4)i + (q+12)j [1 mark]
(b) Values p & q: p=14, q=-17 [2 marks]
(c) Distance = 17.9m [3 marks]

Q3 - Toy car
(a) Acceleration = 1.5 ms^-2 [2 marks]
(b) Velocity = 1.8 m/s [2 marks]
(c) Angle of slope = 8.80 ~ 9 degrees [4 marks]
mgsintheta=ma
mgsintheta=m(1.5)
gsintheta=1.5

Q4 - Resultant velocity
(a) 240m due East at t=20 so
V=12 m/s [2 mark]
(b) Resultant velocity = 90.8 m/s [2 marks]
(c) Bearing = 008 degrees [4 marks]

Q5 - Connected particles
(a) Show that acceleration = 3.92 m/s [5 marks]
(b) Velocity of the particle when it hits the ground = 2.50 m/s [2 marks]
(c) String becomes slack when particle moves 80cm, calculate the maximum height of the other particle = 1.12 m [3 marks]

Q6 - Force T applied to block
(a) Find R in terms of T: R = 5g + Tcos60 [3 marks]
(b) Find the Tension = 43.8 N [6 marks]

Q7 - Projectile
(a) Time taken = 1.76s [5 marks]
(b) Distance = 13.6m [2 marks]
(c) Calculate V when angle remains unchanged = 13.2 m/s [7 marks]

Horizontal: 16.6 = Vcos50t
Sub in either V or t into
Vertical displacement 1=Vsin50t - 4.9t^2
To get a value of t=1.96s
Sub into Horizontal equation to find V= 13.2 m/s

(d) Assumption to why the football is modelled as a particle? [1 mark]
Possibility of rotation
Other possible answers?

Q8 - Vectors [10 marks]
A has an initial velocity 8i+4j and acceleration -0.2i+0.1j, at origin.
B has an initial velocity 6i+9j and acceleration 0.2i-0.1j, initial position vector 40i+50j.
Find the distance between A & B at the instant when velocities are parallel.
Distance = 106 m using t=12

Allocation of marks (this is just my guess)
- Write down displacement vectors in terms of t for both A & B (1 marks)
- Write down velocity vectors in terms of t for both A & B (1 marks)
- Finding values of t using velocity vectors and subbing into displacement vectors (6 marks)
- Subtracting displacements (B-A) to get a final displacement vector & calculate distance by using Pythagoras (2 marks)

I think calculating the wrong value of t would lose 6 marks imo.
There are different ways of doing Q8 I'm sure.

Isn't the expression for 5a R=5g+Tsin60 insted of cos 60 ?

Hey there, I put all the numbers of marks on my graphical calculator to your luck


Here's what you got wrong @Pentaquark,

1b was also 3 marks.
2b was 3 marks.
3a was 3 marks.
3b was 2 marks.
4c was only 3 marks.
5b was 3 marks.
5c was 4 marks.
6a was only 2 marks.


Other than that you've done a cracking job!

Ah I think I'm missing one mark Remember anything? haha
I procrastinated waaay too much by making this lol

Indeed, mhm - Maybe i missed a mark somewhere when typing it in. Anything that strikes out to you as being too low? I know the first resultant one was deffo 1 mark as I remember trying to do magnitude and realising it was 1 mark.

So thats now 2 missing marks argh this is going to annoy me so much.
I'll probably get access to the paper next week if my maths teacher leaves it all on his desk haha.
I think i will just wait for someone else to check it.
Or it will drive me mad.

Wouldn't worry too much about what marks you got, as long as you know you did your best what else can you do? I'm doing lots of Mechanics Units and even Myself and some other Further Maths guys found that paper quite tricky due to the questions being worded a bit funny.

I just want the unofficial ms perfect tho
haha thanks Fingers crossed I might get full UMS
I think I've dropped around ~8 marks so I'm hoping its like June 2014 again.

I need to focus on my last exam anyway which is M2.

Mechanics 2 is a real pain :/ This years paper is gonna be a a hard one. I got a few diff answers to you man btw but maybe I'm wrong idk. Like I said it should be modelled as a particle as then it's assumed the mass is in the center and takes a perfect path ect.