Edexcel M1 2008 January — Question 3 11 marks

Exam BoardEdexcel
ModuleM1 (Mechanics 1)
Year2008
SessionJanuary
Marks11
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicConstant acceleration (SUVAT)
TypeMulti-phase journey: find unknown speed or time
DifficultyStandard +0.3 This is a standard M1 SUVAT problem requiring systematic application of kinematic equations across three motion phases. While it involves multiple stages and an unknown V to solve, the approach is methodical: find deceleration time using v²=u²+2as, calculate acceleration from given time/speeds, then use total distance constraint. The algebraic manipulation is straightforward, making this slightly easier than average for M1.
Spec3.02a Kinematics language: position, displacement, velocity, acceleration3.02b Kinematic graphs: displacement-time and velocity-time3.02d Constant acceleration: SUVAT formulae

3. A car moves along a horizontal straight road, passing two points \(A\) and \(B\). At \(A\) the speed of the car is \(15 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). When the driver passes \(A\), he sees a warning sign \(W\) ahead of him, 120 m away. He immediately applies the brakes and the car decelerates with uniform deceleration, reaching \(W\) with speed \(5 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). At \(W\), the driver sees that the road is clear. He then immediately accelerates the car with uniform acceleration for 16 s to reach a speed of \(V \mathrm {~m} \mathrm {~s} ^ { - 1 } ( V > 15 )\). He then maintains the car at a constant speed of \(V \mathrm {~m} \mathrm {~s} ^ { - 1 }\). Moving at this constant speed, the car passes \(B\) after a further 22 s .
  1. Sketch, in the space below, a speed-time graph to illustrate the motion of the car as it moves from \(A\) to \(B\).
  2. Find the time taken for the car to move from \(A\) to \(B\). The distance from \(A\) to \(B\) is 1 km .
  3. Find the value of \(V\).

Question 3:
Part (a)
AnswerMarks Guidance
WorkingMarks Notes
Shape 'V'B1
Shape for last 22s (with \(V > 15\))B1
Figures: 15, 5, \(t\), 16, 22 on axesB1 (3)
Part (b)
AnswerMarks Guidance
WorkingMarks Notes
\(\frac{1}{2}(15+5) \times t = 120\)M1
\(\Rightarrow t = 12 \rightarrow T = 12 + 16 + 22 = 50\text{ s}\)M1 A1 (3)
Part (c)
AnswerMarks Guidance
WorkingMarks Notes
\(120 + \frac{1}{2}(V+5) \cdot 16 + 22V = 1000\)M1 B1 A1
Solve: \(30V = 840 \Rightarrow V = 28\)DM1 A1 (5) Total: 11
## Question 3:

### Part (a)
| Working | Marks | Notes |
|---------|-------|-------|
| Shape 'V' | B1 | |
| Shape for last 22s (with $V > 15$) | B1 | |
| Figures: 15, 5, $t$, 16, 22 on axes | B1 (3) | |

### Part (b)
| Working | Marks | Notes |
|---------|-------|-------|
| $\frac{1}{2}(15+5) \times t = 120$ | M1 | |
| $\Rightarrow t = 12 \rightarrow T = 12 + 16 + 22 = 50\text{ s}$ | M1 A1 (3) | |

### Part (c)
| Working | Marks | Notes |
|---------|-------|-------|
| $120 + \frac{1}{2}(V+5) \cdot 16 + 22V = 1000$ | M1 B1 A1 | |
| Solve: $30V = 840 \Rightarrow V = 28$ | DM1 A1 (5) | **Total: 11** |

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3. A car moves along a horizontal straight road, passing two points $A$ and $B$. At $A$ the speed of the car is $15 \mathrm {~m} \mathrm {~s} ^ { - 1 }$. When the driver passes $A$, he sees a warning sign $W$ ahead of him, 120 m away. He immediately applies the brakes and the car decelerates with uniform deceleration, reaching $W$ with speed $5 \mathrm {~m} \mathrm {~s} ^ { - 1 }$. At $W$, the driver sees that the road is clear. He then immediately accelerates the car with uniform acceleration for 16 s to reach a speed of $V \mathrm {~m} \mathrm {~s} ^ { - 1 } ( V > 15 )$. He then maintains the car at a constant speed of $V \mathrm {~m} \mathrm {~s} ^ { - 1 }$. Moving at this constant speed, the car passes $B$ after a further 22 s .
\begin{enumerate}[label=(\alph*)]
\item Sketch, in the space below, a speed-time graph to illustrate the motion of the car as it moves from $A$ to $B$.
\item Find the time taken for the car to move from $A$ to $B$.

The distance from $A$ to $B$ is 1 km .
\item Find the value of $V$.
\end{enumerate}

\hfill \mbox{\textit{Edexcel M1 2008 Q3 [11]}}