2016 Unofficial M1 Mark Scheme? 2016

The coefficient question was μ=0.73

was that question 5?

These are my answers:

1(a) 104, (90+14)

1(b) p = (400+15t)i + (20t)j
q = (20t)i + (800-5t)j

1(c) The 'j' vectors for both are equal, as it is due west.
800-5t = 20t
t = 32
therefore q = 640i + 640j

2(a) T = 20.6N
2(b) 15.45 N => 15.5 N (3sf)

3(a) Acceleration = -g/8
velocity after rebound = 3.5
thus Impulse = 3 Ns

4(a)
4(b) Area under graph = 975
Area for slower car for first 25 seconds = 750
975-750 = 225
1/2 * b * 30 =225
b = 15
total time = 15+25 = 40
so area under faster car = 975 = 1/2 * (40)(T+40)
T = 8.75 s

5) μ = 0.73

6) For 1st situation, R(T) = 0
For 2nd situation, R(S) = 0

M(S) => 0.5M = 30d-15
M(T) => M = 60 - 15d
Therefore,
d = 1.2m
M = 42kg

7(a) F2 = 2.5i + 2.5j (this required simultaneous equations)
(b) V = 12i +5j, thus speed = 13 ms-1

8(a) Fmax = 0.3g
acceleration = 0.6g
Tension = 11.76N = 11.8 N (3sf)

8(b) RF = √(11.76)^2 + (11.76)^2 = 16.6
It has a bearing of 225

These are all correct from my memory. The only contentious issue is surround 8(b), where most are uncertain as to what would qualify for the mark with regards to the direction.

past mark schemes have just needed to state the angle

I said '45 degrees to both tensions' in words and a diagram showing R going inwards without the angle on it......

you may get the mark for that, I just put that the tension was at an angle of 45 degrees to the horizontal plane and vertical rope

Estimates for grade boundries/UMS?

past mark schemes have just needed to state the angle

Okay that's good then. I guess the only place I lost marks then was getting 1.7 for F2, I just assumed they wanted the magnitude...

These are all correct from my memory. The only contentious issue is surround 8(b), where most are uncertain as to what would qualify for the mark with regards to the direction.

you may get the mark for that, I just put that the tension was at an angle of 45 degrees to the horizontal plane and vertical rope

I said force acts at 45 degrees below horizontal. Would that be enough?

well if you worked out what F2 was then did the magnitude, they may just mark your answer as correct and ignore subsequent working