Question 3:
--- 3(a) ---
3(a) | Equation of motion for whole system. | M1
F 6 4 0 1 1 0 0 g s i n 1 1 0 0 a  − − = | A1 A1
1 5 0 0 0
Use of P=Fv F = ( = 1 2 5 0 )
1 2 | M1
a=0.16 ( ms−2 ) or a=0.163 ( ms−2 ) | A1
(5)
3(a)
Over-accuracy or under-accuracy is penalised max once per complete
question. Penalise final A mark in the appropriate part.
Use of g = 9.81 or 10 is penalised max once per complete question.
Penalise final A mark in the appropriate part.
If both errors occur, could lose the final two A marks.
M1 | Equation of motion for whole system. All terms required.
Dimensionally correct. Condone sign errors and sin/cos confusion.
May form two equations of motion (van and trailer) and combine to
eliminate T. Condone slip with zeroes for M mark. The forces on the
LHS must be consistent with the mass in the ‘ma’.
 1 
Note that s i n is an accuracy error, not a method error.
2 5
A1 | Unsimplified equation in F or P with at most one error. Missing g
from both weight terms counts as 1 error.
A1 | Correct unsimplified equation in F or P
M1 | Use of P = F v . Condone slip with zeroes for M mark.
A1 | Correct answer, 2 sf or 3 sf.
--- 3(b) ---
3(b) | Work-energy equation for the trailer. | M1
1 1
 2 0 0  1 4 2 = 2 4 0 d + 2 0 0 g  d
2 2 5 | A1 A1
( A B = ) 6 2 ( m ) o r ( A B = ) 6 1 . 6 ( m ) | A1
(4)
(9)
Notes
3(b)
M1 | Work-energy equation. Condone slip with zeroes for M mark.
Dimensionally correct, all terms required and with correct structure:
KE, GPE, WD. No repeats. Must use mass of trailer only. Condone
sign errors and sin / cos confusion. M0 for suvat.
 1 
Note that s i n is an accuracy error, not a method error.
2 5
A1 | Unsimplified equation with at most one error.
A1 | Correct unsimplified equation with mass replaced.
A1 | Correct answer, 2 sf or 3 sf No need for AB =
Question | Scheme | Marks