Edexcel M1 2011 June — Question 4 12 marks

Exam BoardEdexcel
ModuleM1 (Mechanics 1)
Year2011
SessionJune
Marks12
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicTravel graphs
TypeMulti-stage motion with all parameters given
DifficultyModerate -0.8 This is a straightforward kinematics problem using constant acceleration equations and speed-time graphs. All parts involve standard M1 techniques: sketching a trapezoid graph, calculating areas under the graph for distance, and applying suvat equations. The multi-part structure adds length but not conceptual difficulty—each step is routine for M1 students.
Spec3.02b Kinematic graphs: displacement-time and velocity-time3.02d Constant acceleration: SUVAT formulae

A girl runs a 400 m race in a time of 84 s. In a model of this race, it is assumed that, starting from rest, she moves with constant acceleration for 4 s, reaching a speed of 5 m s\(^{-1}\). She maintains this speed for 60 s and then moves with constant deceleration for 20 s, crossing the finishing line with a speed of \(V\) m s\(^{-1}\).
  1. Sketch, in the space below, a speed-time graph for the motion of the girl during the whole race. [2]
  2. Find the distance run by the girl in the first 64 s of the race. [3]
  3. Find the value of \(V\). [5]
  4. Find the deceleration of the girl in the final 20 s of her race. [2]

(a)
AnswerMarks
[Graph showing horizontal line at \(V = 5\) from 0 to 4, constant from 4 to 64, then decreasing linearly to 0 at 84]B1 shape
B1 figs
(2)
(b)
AnswerMarks
\((\frac{1}{2} \times 4 \times 5) + 60 \times 5\)M1 A1
\(= 310\)A1
(3)
(c)
AnswerMarks
\(\frac{(5 + V)}{2} \times 20 = (400-310)\)M1 A2 ft
\(V = 4\)DM1 A1
(5)
(d)
AnswerMarks
\(\frac{5 - 4}{20} = 0.05 \text{ ms}^{-2}\)M1 A1
(2)
12
## (a)
[Graph showing horizontal line at $V = 5$ from 0 to 4, constant from 4 to 64, then decreasing linearly to 0 at 84] | B1 shape |
| | B1 figs |
| (2) |

## (b)
$(\frac{1}{2} \times 4 \times 5) + 60 \times 5$ | M1 A1 |
$= 310$ | A1 |
| (3) |

## (c)
$\frac{(5 + V)}{2} \times 20 = (400-310)$ | M1 A2 ft |
$V = 4$ | **DM1** A1 |
| (5) |

## (d)
$\frac{5 - 4}{20} = 0.05 \text{ ms}^{-2}$ | M1 A1 |
| (2) |
| **12** |

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A girl runs a 400 m race in a time of 84 s. In a model of this race, it is assumed that, starting from rest, she moves with constant acceleration for 4 s, reaching a speed of 5 m s$^{-1}$. She maintains this speed for 60 s and then moves with constant deceleration for 20 s, crossing the finishing line with a speed of $V$ m s$^{-1}$.

\begin{enumerate}[label=(\alph*)]
\item Sketch, in the space below, a speed-time graph for the motion of the girl during the whole race. [2]

\item Find the distance run by the girl in the first 64 s of the race. [3]

\item Find the value of $V$. [5]

\item Find the deceleration of the girl in the final 20 s of her race. [2]
\end{enumerate}

\hfill \mbox{\textit{Edexcel M1 2011 Q4 [12]}}