Questions SPS SM Mechanics (39 questions)

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SPS SPS SM Mechanics 2021 May Q1
1.
\includegraphics[max width=\textwidth, alt={}, center]{14759a7d-dbec-4d72-a722-c83043fb59c5-04_607_894_150_644} Three horizontal forces of magnitudes \(F \mathrm {~N} , 8 \mathrm {~N}\) and 10 N act at a point and are in equilibrium. The \(F \mathrm {~N}\) and 8 N forces are perpendicular to each other, and the 10 N force acts at an obtuse angle \(( 90 + \alpha ) ^ { \circ }\) to the \(F \mathrm {~N}\) force (see diagram). Calculate
  1. \(\alpha\),
  2. \(F\).
SPS SPS SM Mechanics 2021 May Q2
2. A particle \(P\) moves with constant acceleration \(( 3 \mathbf { i } - 5 \mathbf { j } ) \mathrm { ms } ^ { - 2 }\). At time \(t = 0\) seconds \(P\) is at the origin. At time \(t = 4\) seconds \(P\) has velocity \(( 2 \mathbf { i } + 4 \mathbf { j } ) \mathrm { ms } ^ { - 1 }\).
  1. Find the displacement vector of \(P\) at time \(t = 4\) seconds.
  2. Find the speed of \(P\) at time \(t = 0\) seconds.
SPS SPS SM Mechanics 2021 May Q3
3. A uniform plank \(A B\) has weight 100 N and length 4 m . The plank rests horizontally in equilibrium on two smooth supports \(C\) and \(D\), where \(A C = x \mathrm {~m}\) and \(C D = 0.5 \mathrm {~m}\) (see diagram).
\includegraphics[max width=\textwidth, alt={}, center]{14759a7d-dbec-4d72-a722-c83043fb59c5-08_184_1266_283_402} The magnitude of the reaction of the support on the plank at \(C\) is 75 N . Modelling the plank as a rigid rod, find
  1. the magnitude of the reaction of the support on the plank at \(D\),
  2. the value of \(x\). A stone block, which is modelled as a particle, is now placed at the end of the plank at \(B\) and the plank is on the point of tilting about \(D\).
  3. Find the weight of the stone block.
  4. Explain the limitation of modelling
    (a) the stone block as a particle,
    (b) the plank as a rigid rod.
SPS SPS SM Mechanics 2021 May Q4
4. A particle \(P\) projected from a point \(O\) on horizontal ground hits the ground after 2.4 seconds. The horizontal component of the initial velocity of \(P\) is \(\frac { 5 } { 3 } d \mathrm {~ms} ^ { - 1 }\).
  1. Find, in terms of \(d\), the horizontal distance of \(P\) from \(O\) when it hits the ground.
  2. Find the vertical component of the initial velocity of \(P\).
    \(P\) just clears a vertical wall which is situated at a horizontal distance \(d \mathrm {~m}\) from \(O\).
  3. Find the height of the wall. The speed of \(P\) as it passes over the wall is \(16 \mathrm {~ms} ^ { - 1 }\).
  4. Find the value of \(d\) correct to 3 significant figures.
SPS SPS SM Mechanics 2021 May Q5
5.
\includegraphics[max width=\textwidth, alt={}, center]{14759a7d-dbec-4d72-a722-c83043fb59c5-12_501_880_132_614} Two particles \(P\) and \(Q\) are attached to opposite ends of a light inextensible string which passes over a small smooth pulley at the top of a rough plane inclined at \(30 ^ { \circ }\) to the horizontal. \(P\) has mass 0.2 kg and is held at rest on the plane. \(Q\) has mass 0.2 kg and hangs freely. The string is taut (see diagram). The coefficient of friction between \(P\) and the plane is 0.4 . The particle \(P\) is released.
  1. State the tension in the string before \(P\) is released, and find the tension in the string after \(P\) is released.
    \(Q\) strikes the floor and remains at rest. \(P\) continues to move up the plane for a further distance of 0.8 m before it comes to rest. \(P\) does not reach the pulley.
  2. Find the speed of the particles immediately before \(Q\) strikes the floor.
  3. Calculate the magnitude of the contact force exerted on \(P\) by the plane while \(P\) is in motion. End of Examination Extra Answer Space
SPS SPS SM Mechanics 2021 September Q1
  1. A racing car starts from rest at the point \(A\) and moves with constant acceleration.of \(11 \mathrm {~m} \mathrm {~s} ^ { - 2 }\) for 8 s . The velocity it has reached after 8 s is then maintained for \(T \mathrm {~s}\). The racing car then decelerates from this velocity to \(40 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) in a further 2 s , reaching point \(B\).
    a Sketch a velocity-time graph to illustrate the motion of the racing car. Include the top speed of the racing car in your sketch.
    b Given that the distance between \(A\) and \(B\) is 1404 m , find the value of \(T\).
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  2. A particle \(P\) is acted upon by three forces \(\mathbf { F } _ { 1 } , \mathbf { F } _ { 2 }\) and \(\mathbf { F } _ { 3 }\) given by \(\mathbf { F } _ { 1 } = ( 6 \mathbf { i } - 4 \mathbf { j } ) \mathrm { N } , \mathbf { F } _ { 2 } = ( - 2 \mathbf { i } + 9 \mathbf { j } ) \mathrm { N }\) and \(\mathbf { F } _ { 3 } = ( a \mathbf { i } + b \mathbf { j } ) \mathrm { N }\), where \(a\) and \(b\) are constants. Given that \(P\) is in equilibrium,
    a find the value of \(a\) and the value of \(b\).
The force \(\mathbf { F } _ { 2 }\) is now removed. The resultant of \(\mathbf { F } _ { 1 }\) and \(\mathbf { F } _ { 3 }\) is \(\mathbf { R }\).
b Find the magnitude of \(\mathbf { R }\).
c Find the angle, to \(0.1 ^ { \circ }\), that \(\mathbf { R }\) makes with \(\mathbf { i }\).
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SPS SPS SM Mechanics 2021 September Q3
3. A car of mass 1200 kg pulls a trailer of mass 400 kg along a straight horizontal road. The car and trailer are connected by a tow-rope modelled as a light inextensible rod. The engine of the car provides a constant driving force of 3200 N . The horizontal resistances of the car and the trailer are proportional to their respective masses. Given that the acceleration of the car and the trailer is \(0.4 \mathrm {~m} \mathrm {~s} ^ { - 2 }\),
a find the resistance to motion on the trailer,
b find the tension in the tow-rope. When the car and trailer are travelling at \(25 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) the tow-rope breaks. Assuming that the resistances to motion remain unchanged,
c find the distance the trailer travels before coming to a stop,
d state how you have used the modelling assumption that the tow-rope is inextensible.
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SPS SPS SM Mechanics 2021 September Q4
4. A car starts from the point \(A\). At time \(t \mathrm {~s}\) after leaving \(A\), the distance of the car from \(A\) is \(s \mathrm {~m}\), where \(s = 30 t - 0.4 t ^ { 2 } , 0 \leqslant t \leqslant 25\). The car reaches the point \(B\) when \(t = 25\).
a Find the distance \(A B\).
b Show that the car travels with a constant acceleration and state the value of this acceleration. A runner passes through \(B\) when \(t = 0\) with an initial velocity of \(2 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) running directly towards \(A\). The runner has a constant acceleration of \(0.1 \mathrm {~m} \mathrm {~s} ^ { - 2 }\).
c Find the distance from \(A\) at which the runner and the car pass one another.
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SPS SPS SM Mechanics 2022 February Q1
1. Answer all the questions.
Find $$\int \left( x ^ { 4 } - 6 x ^ { 2 } + 7 \right) \mathrm { d } x$$ giving your answer in simplest form.
(3)
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SPS SPS SM Mechanics 2022 February Q2
2. Given that $$\mathrm { f } ( x ) = x ^ { 2 } - 4 x + 5 \quad x \in \mathbb { R }$$
  1. express \(\mathrm { f } ( x )\) in the form \(( x + a ) ^ { 2 } + b\) where \(a\) and \(b\) are integers to be found. The curve with equation \(y = \mathrm { f } ( x )\)
    • meets the \(y\)-axis at the point \(P\)
    • has a minimum turning point at the point \(Q\)
    • Write down
      1. the coordinates of \(P\)
      2. the coordinates of \(Q\)
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SPS SPS SM Mechanics 2022 February Q3
3. The sequence \(u _ { 1 } , u _ { 2 } , u _ { 3 } , \ldots\) is defined by $$u _ { n + 1 } = k - \frac { 24 } { u _ { n } } \quad u _ { 1 } = 2$$ where \(k\) is an integer.
Given that \(u _ { 1 } + 2 u _ { 2 } + u _ { 3 } = 0\)
  1. show that $$3 k ^ { 2 } - 58 k + 240 = 0$$
  2. Find the value of \(k\), giving a reason for your answer.
  3. Find the value of \(u _ { 3 }\)
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SPS SPS SM Mechanics 2022 February Q4
4. Relative to a fixed origin \(O\),
  • the point \(A\) has position vector \(5 \mathbf { i } + 3 \mathbf { j } - 2 \mathbf { k }\)
  • the point \(B\) has position vector \(7 \mathbf { i } + \mathbf { j } + 2 \mathbf { k }\)
  • the point \(C\) has position vector \(4 \mathbf { i } + 8 \mathbf { j } - 3 \mathbf { k }\)
    1. Find \(| \overrightarrow { A B } |\) giving your answer as a simplified surd.
Given that \(A B C D\) is a parallelogram,
  • find the position vector of the point \(D\). The point \(E\) is positioned such that
    • \(A C E\) is a straight line
    • \(A C : C E = 2 : 1\)
    • Find the coordinates of the point \(E\).
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    \section*{Solutions relying entirely on calculator technology are not acceptable.} \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{eacf7695-44c4-4937-8e92-5b0df8ad5f70-12_855_1104_340_589} \captionsetup{labelformat=empty} \caption{Figure 2}
    \end{figure} Figure 2 shows a sketch of part of the curve \(C\) with equation $$y = x ^ { 3 } - 10 x ^ { 2 } + 27 x - 23$$ The point \(P ( 5 , - 13 )\) lies on \(C\)
    The line \(l\) is the tangent to \(C\) at \(P\)
  • Use differentiation to find the equation of \(l\), giving your answer in the form \(y = m x + c\) where \(m\) and \(c\) are integers to be found.
  • Hence verify that \(l\) meets \(C\) again on the \(y\)-axis. The finite region \(R\), shown shaded in Figure 2, is bounded by the curve \(C\) and the line \(l\).
  • Use algebraic integration to find the exact area of \(R\).
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  • SPS SPS SM Mechanics 2022 February Q6
    6. A scientist is studying the growth of two different populations of bacteria. The number of bacteria, \(N\), in the first population is modelled by the equation $$N = A \mathrm { e } ^ { k t } \quad t \geqslant 0$$ where \(A\) and \(k\) are positive constants and \(t\) is the time in hours from the start of the study.
    Given that
    • there were 1000 bacteria in this population at the start of the study
    • it took exactly 5 hours from the start of the study for this population to double
      1. find a complete equation for the model.
      2. Hence find the rate of increase in the number of bacteria in this population exactly 8 hours from the start of the study. Give your answer to 2 significant figures.
    The number of bacteria, \(M\), in the second population is modelled by the equation $$M = 500 \mathrm { e } ^ { 1.4 k t } \quad t \geqslant 0$$ where \(k\) has the value found in part (a) and \(t\) is the time in hours from the start of the study.
    Given that \(T\) hours after the start of the study, the number of bacteria in the two different populations was the same,
  • find the value of \(T\).
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  • Show that $$\frac { 1 - \cos 2 \theta } { \sin ^ { 2 } 2 \theta } \equiv k \sec ^ { 2 } \theta \quad \theta \neq \frac { n \pi } { 2 } \quad n \in \mathbb { Z }$$ where \(k\) is a constant to be found.
  • Hence solve, for \(- \frac { \pi } { 2 } < x < \frac { \pi } { 2 }\) $$\frac { 1 - \cos 2 x } { \sin ^ { 2 } 2 x } = ( 1 + 2 \tan x ) ^ { 2 }$$ Give your answers to 3 significant figures where appropriate.
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  • SPS SPS SM Mechanics 2022 February Q8
    8. Show that $$\sum _ { n = 2 } ^ { \infty } \left( \frac { 3 } { 4 } \right) ^ { n } \cos ( 180 n ) ^ { \circ } = \frac { 9 } { 28 }$$ [BLANK PAGE]
    SPS SPS SM Mechanics 2022 February Q9
    9. The function f is defined by $$\mathrm { f } ( x ) = \frac { ( x + 5 ) ( x + 1 ) } { ( x + 4 ) } - \ln ( x + 4 ) \quad x \in \mathbb { R } \quad x > k$$
    1. State the smallest possible value of \(k\).
    2. Show that $$\mathrm { f } ^ { \prime } ( x ) = \frac { a x ^ { 2 } + b x + c } { ( x + 4 ) ^ { 2 } }$$ where \(a\), \(b\) and \(c\) are integers to be found.
    3. Hence show that f is an increasing function.
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    SPS SPS SM Mechanics 2022 February Q10
    10. \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{eacf7695-44c4-4937-8e92-5b0df8ad5f70-24_707_716_255_826} \captionsetup{labelformat=empty} \caption{Figure 4}
    \end{figure} Figure 4 shows a sketch of the graph with equation $$y = | 2 x - 3 k |$$ where \(k\) is a positive constant.
    1. Sketch the graph with equation \(y = \mathrm { f } ( x )\) where $$\mathrm { f } ( x ) = k - | 2 x - 3 k |$$ stating
      • the coordinates of the maximum point
      • the coordinates of any points where the graph cuts the coordinate axes
      • Find, in terms of \(k\), the set of values of \(x\) for which
      $$k - | 2 x - 3 k | > x - k$$ giving your answer in set notation.
    2. Find, in terms of \(k\), the coordinates of the minimum point of the graph with equation $$y = 3 - 5 \mathrm { f } \left( \frac { 1 } { 2 } x \right)$$ [BLANK PAGE]
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    SPS SPS SM Mechanics 2022 February Q11
    11. The curve \(C\) has parametric equations $$x = \sin 2 \theta \quad y = \operatorname { cosec } ^ { 3 } \theta \quad 0 < \theta < \frac { \pi } { 2 }$$
    1. Find an expression for \(\frac { \mathrm { d } y } { \mathrm {~d} x }\) in terms of \(\theta\)
    2. Hence find the exact value of the gradient of the tangent to \(C\) at the point where \(y = 8\)
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    SPS SPS SM Mechanics 2022 February Q12
    12. Answer all the questions.
    Two cyclists, \(A\) and \(B\), are cycling along the same straight horizontal track.
    The cyclists are modelled as particles and the motion of the cyclists is modelled as follows:
    • At time \(t = 0\), cyclist \(A\) passes through the point \(O\) with speed \(2 \mathrm {~ms} ^ { - 1 }\)
    • Cyclist \(A\) is moving in a straight line with constant acceleration \(2 \mathrm {~m} \mathrm {~s} ^ { - 2 }\)
    • At time \(t = 2\) seconds, cyclist \(B\) starts from rest at \(O\)
    • Cyclist \(B\) moves with constant acceleration \(6 \mathrm {~m} \mathrm {~s} ^ { - 2 }\) along the same straight line and in the same direction as cyclist \(A\)
    • At time \(t = T\) seconds, \(B\) overtakes \(A\) at the point \(X\)
    Using the model,
    1. sketch, on the same axes, for the interval from \(t = 0\) to \(t = T\) seconds,
      • a velocity-time graph for the motion of \(A\)
      • a velocity-time graph for the motion of \(B\)
      • explain why the two graphs must cross before time \(t = T\) seconds,
      • find the time when \(A\) and \(B\) are moving at the same speed,
      • find the distance \(O X\)
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    SPS SPS SM Mechanics 2022 February Q13
    13.
    \includegraphics[max width=\textwidth, alt={}]{eacf7695-44c4-4937-8e92-5b0df8ad5f70-34_328_1520_132_251}
    A golfer hits a ball from a point \(A\) with a speed of \(25 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) at an angle of \(15 ^ { \circ }\) above the horizontal. While the ball is in the air, it is modelled as a particle moving under the influence of gravity. Take the acceleration due to gravity to be \(10 \mathrm {~m} \mathrm {~s} ^ { - 2 }\). The ball first lands at a point \(B\) which is 4 m below the level of \(A\) (see diagram).
    1. Determine the time taken for the ball to travel from \(A\) to \(B\).
    2. Determine the horizontal distance of \(B\) from \(A\).
    3. Determine the direction of motion of the ball 1.5 seconds after the golfer hits the ball.
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    SPS SPS SM Mechanics 2022 February Q14
    14.
    \includegraphics[max width=\textwidth, alt={}, center]{eacf7695-44c4-4937-8e92-5b0df8ad5f70-36_527_1123_118_269} One end of a light inextensible string is attached to a particle \(A\) of mass 2 kg . The other end of the string is attached to a second particle \(B\) of mass 3 kg . Particle \(A\) is in contact with a smooth plane inclined at \(30 ^ { \circ }\) to the horizontal and particle \(B\) is in contact with a rough horizontal plane. A second light inextensible string is attached to \(B\). The other end of this second string is attached to a third particle \(C\) of mass 4 kg . Particle \(C\) is in contact with a smooth plane \(\Pi\) inclined at an angle of \(60 ^ { \circ }\) to the horizontal. Both strings are taut and pass over small smooth pulleys that are at the tops of the inclined planes. The parts of the strings from \(A\) to the pulley, and from \(C\) to the pulley, are parallel to lines of greatest slope of the corresponding planes (see diagram). The coefficient of friction between \(B\) and the horizontal plane is \(\mu\). The system is released from rest and in the subsequent motion \(C\) moves down \(\Pi\) with acceleration \(a \mathrm {~ms} ^ { - 2 }\).
    1. By considering an equation involving \(\mu , a\) and \(g\) show that \(a < \frac { 1 } { 9 } g ( 2 \sqrt { 3 } - 1 )\).
    2. Given that \(a = \frac { 1 } { 9 } g\), determine the magnitude of the contact force between \(B\) and the horizontal plane. Give your answer correct to \(\mathbf { 3 }\) significant figures.
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    SPS SPS SM Mechanics 2023 January Q1
    1. 10 seconds after passing a warning signal, a train is travelling at \(18 m s ^ { - 1 }\) and has gone 215 m beyond the signal. Find the acceleration (assumed to be constant) of the train during the 10 seconds and its velocity as it passed the signal.
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    SPS SPS SM Mechanics 2023 January Q2
    2. A particle of mass \(m\) is placed on a rough inclined plane.
    The plane makes an angle \(\theta\) with the horizontal.
    The coefficient of friction between the particle and the plane is \(\mu\) where \(\mu < \tan \theta\). The particle is released from rest and accelerates down the plane.
    1. Draw a fully labelled diagram to show the forces acting on the particle.
    2. Find an expression in terms of \(g , \theta\) and \(\mu\) for the acceleration of the particle.
    3. Explain what would happen to the particle if \(\mu > \tan \theta\). \section*{BLANK PAGE FOR WORKING}
    SPS SPS SM Mechanics 2023 January Q3
    1. A parcel \(P\) of weight 50 N is being held in equilibrium by two light, inextensible strings \(A P\) and \(B P\). The string \(A P\) is attached to a wall at \(A\), and string \(B P\) passes over a smooth pulley which is at the same height as \(A\), as shown in the diagram.
    When the tension in \(B P\) is 40 N , the strings are at right angles to each other.
    \includegraphics[max width=\textwidth, alt={}, center]{4109fba0-077e-472b-b37f-7ac2e45aacc7-08_531_768_479_699}
    1. Find the tension in string \(A P\).
    2. Explain why the parcel can never be in equilibrium, with both strings horizontal. \section*{BLANK PAGE FOR WORKING}
    SPS SPS SM Mechanics 2023 January Q4
    4. \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{4109fba0-077e-472b-b37f-7ac2e45aacc7-10_680_1218_141_466} \captionsetup{labelformat=empty} \caption{Figure 1}
    \end{figure} A small ball, \(P\), of mass 0.8 kg , is held at rest on a smooth horizontal table and is attached to one end of a thin rope. The rope passes over a pulley that is fixed at the edge of the table.
    The other end of the rope is attached to another small ball, \(Q\), of mass 0.6 kg , that hangs freely below the pulley. Ball \(P\) is released from rest, with the rope taut, with \(P\) at a distance of 1.5 m from the pulley and with \(Q\) at a height of 0.4 m above the horizontal floor, as shown in Figure 1. Ball \(Q\) descends, hits the floor and does not rebound.
    The balls are modelled as particles, the rope as a light and inextensible string and the pulley as small and smooth. Using this model,
    1. show that the acceleration of \(Q\), as it falls, is \(4.2 \mathrm {~ms} ^ { - 2 }\)
    2. find the time taken by \(P\) to hit the pulley from the instant when \(P\) is released.
    3. State one limitation of the model that will affect the accuracy of your answer to part (a). \section*{BLANK PAGE FOR WORKING}
    SPS SPS SM Mechanics 2023 January Q5
    1. At time \(t\) seconds, where \(0 \leq t \leq T\), a particle, \(P\), moves so that its velocity \(v m s ^ { - 1 }\) is given by
    $$v = 7.2 t - 0.45 t ^ { 2 }$$ When \(t = 0\) the particle is sitting stationary at a displacement of \(\mathrm { d } m\) from a point O .
    The particle's acceleration is zero when \(t = T\).
    1. Find the value of \(T\). For \(t \geq T\), the particle moves with a velocity \(v = 48 - 2.4 t m s ^ { - 1 }\).
    2. Find the time when \(P\) is at its maximum displacement from O . The particle passes through the point O when \(t = 38\).
    3. Find \(d\). \section*{BLANK PAGE FOR WORKING}