CAIE M1 2017 June — Question 3 6 marks

Exam BoardCAIE
ModuleM1 (Mechanics 1)
Year2017
SessionJune
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicConstant acceleration (SUVAT)
TypeMulti-phase journey: find unknown speed or time
DifficultyStandard +0.3 This is a standard SUVAT problem requiring students to work with a trapezoid velocity-time graph, set up algebraic expressions involving T, and solve for distances. While it has multiple parts and requires careful algebraic manipulation, it follows a very familiar pattern for M1 students with no novel insights needed—slightly easier than average.
Spec3.02b Kinematic graphs: displacement-time and velocity-time3.02c Interpret kinematic graphs: gradient and area3.02d Constant acceleration: SUVAT formulae

3 A train travels between two stations, \(A\) and \(B\). The train starts from rest at \(A\) and accelerates at a constant rate for \(T\) s until it reaches a speed of \(25 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). It then travels at this constant speed before decelerating at a constant rate, coming to rest at \(B\). The magnitude of the train's deceleration is twice the magnitude of its acceleration. The total time taken for the journey is 180 s .
  1. Sketch the velocity-time graph for the train's journey from \(A\) to \(B\). \includegraphics[max width=\textwidth, alt={}, center]{3d7f53af-dbf2-499b-9966-ae85514cef02-04_496_857_516_685}
  2. Find an expression, in terms of \(T\), for the length of time for which the train is travelling with constant speed.
  3. The distance from \(A\) to \(B\) is 3300 m . Find how far the train travels while it is decelerating.

Question 3:
Part (i)
AnswerMarks Guidance
AnswerMarks Guidance
Trapezium, right-hand steeper than left-hand slopeB1
Total: 1
Part (ii)
AnswerMarks Guidance
AnswerMarks Guidance
Deceleration \(0.5T\)B1 May be implied
Constant speed \(180 - 1.5T\)B1
Total: 2
Part (iii)
AnswerMarks Guidance
AnswerMarks Guidance
\(0.5[180 + (180 - 1.5T)] \times 25 = 3300\)M1 Uses area property
\(T = 64\)A1
Distance decelerating \(= [0.5 \times 32 \times 25 =]\ 400\) mB1
Total: 3
## Question 3:

### Part (i)
| Answer | Marks | Guidance |
|--------|-------|----------|
| Trapezium, right-hand steeper than left-hand slope | B1 | |
| **Total: 1** | | |

### Part (ii)
| Answer | Marks | Guidance |
|--------|-------|----------|
| Deceleration $0.5T$ | B1 | May be implied |
| Constant speed $180 - 1.5T$ | B1 | |
| **Total: 2** | | |

### Part (iii)
| Answer | Marks | Guidance |
|--------|-------|----------|
| $0.5[180 + (180 - 1.5T)] \times 25 = 3300$ | M1 | Uses area property |
| $T = 64$ | A1 | |
| Distance decelerating $= [0.5 \times 32 \times 25 =]\ 400$ m | B1 | |
| **Total: 3** | | |

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3 A train travels between two stations, $A$ and $B$. The train starts from rest at $A$ and accelerates at a constant rate for $T$ s until it reaches a speed of $25 \mathrm {~m} \mathrm {~s} ^ { - 1 }$. It then travels at this constant speed before decelerating at a constant rate, coming to rest at $B$. The magnitude of the train's deceleration is twice the magnitude of its acceleration. The total time taken for the journey is 180 s .\\
(i) Sketch the velocity-time graph for the train's journey from $A$ to $B$.\\
\includegraphics[max width=\textwidth, alt={}, center]{3d7f53af-dbf2-499b-9966-ae85514cef02-04_496_857_516_685}\\
(ii) Find an expression, in terms of $T$, for the length of time for which the train is travelling with constant speed.\\

(iii) The distance from $A$ to $B$ is 3300 m . Find how far the train travels while it is decelerating.\\

\hfill \mbox{\textit{CAIE M1 2017 Q3 [6]}}