Maths Answers
Maths Answers
6677/01
                 Edexcel GCE
                 Mechanics M1
                 Advanced Subsidiary
                 Monday 13 May 2013  Afternoon
                 Time: 1 hour 30 minutes
                 Candidates may use any calculator allowed by the regulations of the Joint
                 Council for Qualifications. Calculators must not have the facility for symbolic
                 algebra manipulation, differentiation and integration, or have retrievable
                 mathematical formulae stored in them.
Instructions to Candidates
In the boxes on the answer book, write the name of the examining body (Edexcel), your
centre number, candidate number, the unit title (Mechanics M1), the paper reference (6677),
your surname, other name and signature.
Whenever a numerical value of g is required, take g = 9.8 m s2.
When a calculator is used, the answer should be given to an appropriate degree of accuracy.
Advice to Candidates
You must ensure that your answers to parts of questions are clearly labelled.
You must show sufficient working to make your methods clear to the Examiner.
Answers without working may not gain full credit.
P41828A          This publication may only be reproduced in accordance with Edexcel Limited copyright policy.
                 ©2013 Edexcel Limited.
1.   Particle P has mass 3 kg and particle Q has mass m kg. The particles are moving in opposite
     directions along a smooth horizontal plane when they collide directly. Immediately before the
     collision, the speed of P is 4 m s–1 and the speed of Q is 3 m s–1. In the collision the direction
     of motion of P is unchanged and the direction of motion of Q is reversed. Immediately after
     the collision, the speed of P is 1 m s–1 and the speed of Q is 1.5 m s–1.
2.   A woman travels in a lift. The mass of the woman is 50 kg and the mass of the lift is 950 kg.
     The lift is being raised vertically by a vertical cable which is attached to the top of the lift.
     The lift is moving upwards and has constant deceleration of 2 m s–2. By modelling the cable
     as being light and inextensible, find
3.
Figure 1
     A box of mass 2 kg is held in equilibrium on a fixed rough inclined plane by a rope. The rope
     lies in a vertical plane containing a line of greatest slope of the inclined plane. The rope is
     inclined to the plane at an angle , where tan  = 34 , and the plane is at an angle of 30° to the
     horizontal, as shown in Figure 1. The coefficient of friction between the box and the inclined
     plane is 13 and the box is on the point of slipping up the plane. By modelling the box as a
     particle and the rope as a light inextensible string, find the tension in the rope.
                                                                                                    (8)
     P41828A                                          2
4.   A lorry is moving along a straight horizontal road with constant acceleration. The lorry passes
     a point A with speed u m s–1, (u < 34), and 10 seconds later passes a point B with speed
     34 m s–1. Given that AB = 240 m, find
5.   A car is travelling along a straight horizontal road. The car takes 120 s to travel between two
     sets of traffic lights which are 2145 m apart. The car starts from rest at the first set of traffic
     lights and moves with constant acceleration for 30 s until its speed is 22 m s–1. The car
     maintains this speed for T seconds. The car then moves with constant deceleration, coming to
     rest at the second set of traffic lights.
     (a) Sketch a speed-time graph for the motion of the car between the two sets of traffic lights.
                                                                                                 (2)
     (b) Find the value of T.
                                                                                                         (3)
     A motorcycle leaves the first set of traffic lights 10 s after the car has left the first set of traffic
     lights. The motorcycle moves from rest with constant acceleration, a m s–2, and passes the car
     at the point A which is 990 m from the first set of traffic lights. When the motorcycle passes
     the car, the car is moving with speed 22 m s–1.
     (c) Find the time it takes for the motorcycle to move from the first set of traffic lights to the
         point A.
                                                                                                   (4)
     (d) Find the value of a.
                                                                                                         (2)
     P41828A                                             3
6.   A beam AB has length 15 m. The beam rests horizontally in equilibrium on two smooth
     supports at the points P and Q, where AP = 2 m and QB = 3 m. When a child of mass 50 kg
     stands on the beam at A, the beam remains in equilibrium and is on the point of tilting
     about P. When the same child of mass 50 kg stands on the beam at B, the beam remains in
     equilibrium and is on the point of tilting about Q. The child is modelled as a particle and the
     beam is modelled as a non-uniform rod.
         (ii) Find the distance of the centre of mass of the beam from A.
                                                                                                 (8)
     When the child stands at the point X on the beam, it remains horizontal and in equilibrium.
     Given that the reactions at the two supports are equal in magnitude,
7.   [In this question, the horizontal unit vectors i and j are directed due east and due north
     respectively.]
(i) parallel to j,
     P41828A                                           4
8.
Figure 2
     Two particles A and B have masses 2m and 3m respectively. The particles are attached to the
     ends of a light inextensible string. Particle A is held at rest on a smooth horizontal table. The
     string passes over a small smooth pulley which is fixed at the edge of the table. Particle B
     hangs at rest vertically below the pulley with the string taut, as shown in Figure 2. Particle A
     is released from rest. Assuming that A has not reached the pulley, find
     P41828A                                          5
Question
                                            Scheme                                       Marks
Number
   1.
  (a)      For P,        − I = 3(1 − 4)                                                 M1 A1
                          I = 9 Ns                                                      A1
                                                                                                (3)
  (b)      For Q,         9 = m(1.5 − −3)                                               M1 A1
                         m=2                                                            A1
           OR
                    12 − 3m = 3 + 1.5m                                                  M1 A1
                          m=2                                                           A1
                                                                                                (3)
                                                                                                [6]
           First M1 for resolving parallel to the plane with correct no. of terms and
           both T and 2g terms resolved.
           First A1 for a correct equation. (use of α instead of 30 o or 60 o or vice
           versa is an A error not M error; similarly if they use sin(3/5) or cos(4/5)
           when resolving, this can score M1A0)
           Second M1 for resolving perpendicular to the plane with correct no. of
           terms and both T and 2g terms resolved.
           Second A1 for a correct equation (use of α instead of 30 o or 60 o or
  Q3       vice versa is an A error not M error; similarly if they use sin(3/5) or
           cos(4/5) when resolving, this can score M1A0)
           B1 for F = 1/3 R seen or implied.
           Third M1, dependent on first two M marks and appropriate angles used
           when resolving in both equations, for eliminating F and R.
           Fourth M1 dependent on third M1, for solving for T
           Third A1 for 15(N) or 15.5 (N).
           N.B. The first two M marks can be for two resolutions in any directions.
           Use of tan α = 4/3 leads to an answer of 17.83…and can score max 7/8.
Question
                                              Scheme                                  Marks
Number
   4.
  (a)      240 = 12 (u + 34)10                                                       M1 A1
           u = 14                                                                    A1
                                                                                             (3)
  (b)      34 = 14 + 10a => a = 2                                                    M1 A1
           120 = 14t + × 2 × t
                       1
                       2
                                 2
                                                                                     M1 A1
           t 2 + 14t − 120 = 0
           Solving, t = −20 or 6                                                     DM1
           t =6                                                                      A1
           OR
           34 = 14 + 10a => a = 2                                                    M1 A1
           v 2 = 142 + 2 × 2 × 120 ⇒ v = 26
           AND 26 = 14 + 2t                                                          M1 A1
           t =6                                                                      DM1 A1
                                                                                             (6)
                                                                                             [9]
           First B1 for a trapezium starting at the origin and ending on the t-axis.
 Q5(a)     Second B1 for the figures marked (allow missing 0 and a delineator oe
           for T) (allow if they have used T = 75 correctly on their graph)
           First M1 for producing an equation in their T only by equating the area
           of the trapezium to 2145, with the correct no. of terms. If using a single
           trapezium, we need to see evidence of using ½ the sum of the two
           parallel sides or if using triangle(s), need to see ½ base x height.
 Q5(b)
           Second A1 cao for a correct equation in T (This is not f.t. on their T)
           Third A1 for T = 75.
           N.B. Use of a single suvat equation for the whole motion of the car
            e.g. s =t(u+v)/2 is M0
           First M1 for producing an equation in t only (they may use (t – 30) oe as
           their variable) by equating the area of the trapezium to 990, with the
           correct no. of terms. If using a trapezium, we need to see evidence of
           using ½ the sum of the two parallel sides or if using triangle(s), need to
           see ½ base x height.
           First A1 for a correct equation.
 Q5(c)
           Second A1 for t = 60 (Allow 30 + 30).
           Third A1 for answer of 50.
           N.B. Use of a single suvat equation for the whole motion of the car
            e.g. s =t(u+v)/2 is M0.
           Use of the motion of the motorcycle is M0 (insufficient information).
           Use of v = 22 for the motorcycle is M0.
           First M1 for an equation in a only.
 Q5(d)     First A1 for a = 0.79, 0.792, 99/125 oe
           N.B. Use of v = 22 for the motorcycle is M0.
Question
                                             Scheme                  Marks
Number
   6.
  (a)                 P                                  Q
               A 2m                                          3m B
Mg
xm
           M(P),       50 g × 2 = Mg × ( x − 2)                     M1 A1
           M(Q),       50 g × 3 = Mg × (12 − x )                    M1 A1
        First M1 for moments about P equation with usual rules (or moments
        about a different point AND vertical resolution and R then eliminated)
        (M0 if non-zero reaction at Q)
        Second M1 for moments about Q equation with usual rules (or moments
        about a different point AND vertical resolution) (M0 if non-zero reaction
        at P)
        Second A1 for a correct equation in M and same unknown.
        Third M1, dependent on first and second M marks, for solving for M
Q6(a)
        Third A1 for 25 (kg)
        Fourth M1, dependent on first and second M marks, for solving for x
        Fourth A1 for 6 (m)
        N.B. No marks available if rod is assumed to be uniform but can score
        max 5/6 in part (b), provided they have found values for M and x to f.t.
        on.
        If they have just invented values for M and x in part (a), they can score
        the M marks in part (b) but not the A marks.
        First M1 for vertical resolution or a moments equation, with usual rules.
        First A1 ft on their M and x from part (a), for a correct equation. (must
        have equal reactions in vertical resolution to earn this mark)
        Second M1 for a moments equation with usual rules.
        Second A1 ft on their M and x from part (a), for a correct equation in R
        and same unknown length.
        Third M1, dependent on first and second M marks, for solving for AX
Q6(b)   (not their unknown length) with AX ≤ 15
        Third A1 for AX = 7.5 (m)
        N.B. If a single equation is used (see below), equating the sum of the
        moments of the child and the weight about P to the sum of the moments
        of the child and the weight about Q, this can score M2 A2 ft on their M
        and x from part (a), provided the equation is in one unknown. Any
        method error, loses both M marks.
        e.g. 25g.4 + 50g(x – 2) = 25g.6 + 50g(12 – x) oe.
Question
                                             Scheme                                   Marks
Number
   7.
  (a)      t = 0 gives v = i − 3 j                                                   B1
           speed = 12 + (−3)2                                                        M1
                  = 10 = 3.2 or better                                               A1
                                                                                             (3)
  (b)      t = 2 gives v = (−3i + 3j)                                                M1
                            D
           Bearing is 315                                                            A1
                                                                                             (2)
 (c)(i)    1− 2t = 0 ⇒ t = 0.5                                                       M1 A1
  (ii)      − (3t − 3) = −3(1 − 2t )                                                 M1 A1
           Solving for t                                                             DM1
           t = 2/3, 0.67 or better                                                   A1
                                                                                           (6)
                                                                                          [11]
           B1 for i – 3j.
 Q7(a)     M1 for √ (sum of squares of cpt.s)
           A1 for √10, 3.2 or better
           M1 for clear attempt to sub t = 2 into given expression.
 Q7(b)
           A1 for 315.
              (i)       First M1 for 1 – 2t = 0.
                   First A1 for t = 0.5.
              N.B. If they offer two solutions, by equating both the i and j
              components to zero, give M0.
                                      1− 2t      −1
 Q7(c)        (ii)      First M1 for         = ±( ) o.e. (Must be an equation in t
                                      3t − 3     −3
                        only)
                   First A1 for a correct equation (the + sign)
                   Second M1, dependent on first M1, for solving for t.
                   Second A1 for 2/3, 0.67 or better.
Question
                                            Scheme                                        Marks
Number
   8.
  (a)      For A,           T = 2ma                                                      B1
           For B,    3mg − T = 3ma                                                       M1 A1
                        3mg = 5ma                                                        DM1
                         3g
                             =a        (5.9 or 5.88 m s-2)                               A1
                          5
                                                                                                 (5)
  (b)      T = 6mg/5; 12m ; 11.8m                                                        B1
                                                                                               (1)
  (c)      F = T2 +T2                                                                    M1 A1 ft
               6mg 2
           F=           ;1.7mg (or better);16.6m;17m                                     A1
                   5
           Direction clearly marked on a diagram, with an arrow, and 45o (oe)
                                                                                         B1
           marked
                                                                                               (4)
                                                                                              [10]
           B1 for T = 2ma
           First M1 for resolving vertically (up or down) for B, with correct no. of
           terms. (allow omission of m, provided 3 is there)
           First A1 for a correct equation.
 Q8(a)     Second M1, dependent on first M1, for eliminating T, to give an equation
           in a only.
           Second A1 for 0.6g, 5.88 or 5.9.
           N.B. ‘Whole system’ equation: 3mg = 5ma earns first 4 marks but any
           error loses all 4.
                   6mg
 Q8(b)     B1 for        , 11.8m, 12m
                      5
                                    T           T
           M1 (T 2 + T 2 ) or           o
                                          or        o
                                                      or 2Tcos 45o or 2Tsin 45o (allow
                                 sin 45      cos 45
                   if m omitted)
           (M0 for T sin 45o)
 Q8(c)     First A1 ft on their T.
                                6mg 2
           Second A1 cao for              oe, 1.7mg (or better),16.6m,17m
                                    5
           B1 for the direction clearly shown on a diagram with an arrow and 45o
           marked.