Edexcel M2 2024 June — Question 7 11 marks

Exam BoardEdexcel
ModuleM2 (Mechanics 2)
Year2024
SessionJune
Marks11
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProjectiles
TypeVector form projectile motion
DifficultyModerate -0.3 This is a standard M2 projectile motion question using vector notation. Part (a) requires routine application of range formula with given initial velocity components, while part (b) involves finding when speed exceeds a threshold using the velocity vector magnitude—both are textbook exercises requiring no novel insight, making it slightly easier than average.
Spec3.02d Constant acceleration: SUVAT formulae3.02h Motion under gravity: vector form3.02i Projectile motion: constant acceleration model

  1. \hspace{0pt} [In this question, the unit vectors \(\mathbf { i }\) and \(\mathbf { j }\) are in a vertical plane, \(\mathbf { i }\) being horizontal and j being vertically upwards.]
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{b6e93edf-1b9f-4ea9-bb41-f46f380bc623-22_398_1438_420_267} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} A golf ball is hit from a point \(O\) on horizontal ground and is modelled as a particle moving freely under gravity. The initial velocity of the ball is \(( 2 u \mathbf { i } + u \mathbf { j } ) \mathrm { ms } ^ { - 1 }\) The ball first hits the horizontal ground at a point which is 80 m from \(O\), as shown in Figure 3. Use the model to
  1. show that \(u = 14\)
  2. find the total time, while the ball is in the air, for which the speed of the ball is greater than \(7 \sqrt { 17 } \mathrm {~m} \mathrm {~s} ^ { - 1 }\)

Question 7(a):
AnswerMarks Guidance
Answer/WorkingMark Guidance Notes
Horizontal distanceM1 Equation with correct terms, condone sign errors
\(2ut = 80\)A1 Correct equation
Vertical distance or vertical speedM1 Equation with correct terms, condone sign errors
\(0 = ut - \frac{1}{2}gt^2\)A1 Correct equation in \(t\). Alternatives include \(-u = u - gt\) or \(0 = u - g\frac{1}{2}t\)
Solve for \(u\) \(\left(\text{e.g. } u \times \frac{80}{2u} = \frac{1}{2}g\frac{80^2}{4u^2}\right)\)DM1 Dependent on the two previous M marks
\(u = 14\) *A1* Obtain given answer correctly
Note: If they consistently have \(u\) horizontal and \(2u\) vertically, then mark as a misread: M1A0M1A0M1A1
Total: 6 marks
Question 7(b):
AnswerMarks Guidance
Answer/WorkingMark Guidance Notes
\(v^2 = (7\sqrt{17})^2 - 28^2\)M1 Form an equation in \(v\) only (\(v\) is vertical component)
\(\Rightarrow v = 7\) (or \(-7\))A1 Second value not needed
Use of *suvat* to find the required time. Check logic: time speed is \(< 7\sqrt{17}\) or time speed is \(> 7\sqrt{17}\)?DM1 Dependent on the first M mark. Complete method to obtain the required time, condone sign errors
\(7 = 14 - gt \Rightarrow t = \frac{5}{7} = 0.71\ldots\)A1 Obtain a relevant value of \(t\)
Total time \(= 2 \times \frac{5}{7} = 1.4\) or \(1.43\) (s)A1 For the required time to 2 sf or 3 sf. A0 for \(\frac{10}{7}\); follows the use of an approximate value for \(g\)
Total: 5 marks
Question 7(b) Alternative 1:
AnswerMarks Guidance
Answer/WorkingMark Guidance Notes
\(\frac{1}{2}m(28^2 + 14^2) - \frac{1}{2}m(7\sqrt{17})^2 = mgh\)M1 Form an equation in \(h\) only
\(\Rightarrow h = 7.5\)A1 Correct only
Use of *suvat*; check logic: time speed is \(< 7\sqrt{17}\) or time speed is \(> 7\sqrt{17}\)?DM1 Dependent on the first M mark. Complete method to obtain the required time, condone sign errors
\(7.5 = 14t - \frac{1}{2} \times 9.8t^2 \Rightarrow t = \frac{5}{7},\ t = \frac{15}{7}\)A1 Obtain at least one relevant value of \(t\)
Total time \(= \frac{20}{7} - \left(\frac{15}{7} - \frac{5}{7}\right) = 1.4\) or \(1.43\) (s)A1 For the required time to 2 sf or 3 sf. A0 for \(\frac{10}{7}\); follows the use of an approximate value for \(g\)
Question 7(b) Alternative 2:
AnswerMarks Guidance
Answer/WorkingMark Guidance Notes
Use \(7\sqrt{17}\) to form an equation in \(t\) onlyM1
\(\Rightarrow 7\sqrt{17} = \sqrt{(14 - gt)^2 + 28^2}\)A1 Or equivalent
Solve to find the required time; check logic: time speed is \(< 7\sqrt{17}\) or time speed is \(> 7\sqrt{17}\)?DM1 Dependent on the first M mark. Complete method to obtain the required time, condone sign errors
\(147 = 2gt - g^2t^2 \Rightarrow t = \frac{5}{7},\ t = \frac{15}{7}\)A1 Obtain at least one relevant value of \(t\)
Total time \(= \frac{20}{7} - \left(\frac{15}{7} - \frac{5}{7}\right) = 1.4\) or \(1.43\) (s)A1 For the required time to 2 sf or 3 sf. A0 for \(\frac{10}{7}\); follows the use of an approximate value for \(g\)
Total: 5 marks
The image appears to be essentially blank, containing only the "PMT" watermark in the top right corner and the Pearson Education Limited copyright notice at the bottom. There is no mark scheme content visible on this page to extract.
## Question 7(a):

| Answer/Working | Mark | Guidance Notes |
|---|---|---|
| Horizontal distance | M1 | Equation with correct terms, condone sign errors |
| $2ut = 80$ | A1 | Correct equation |
| Vertical distance or vertical speed | M1 | Equation with correct terms, condone sign errors |
| $0 = ut - \frac{1}{2}gt^2$ | A1 | Correct equation in $t$. Alternatives include $-u = u - gt$ or $0 = u - g\frac{1}{2}t$ |
| Solve for $u$ $\left(\text{e.g. } u \times \frac{80}{2u} = \frac{1}{2}g\frac{80^2}{4u^2}\right)$ | DM1 | Dependent on the two previous M marks |
| $u = 14$ * | A1* | Obtain **given answer** correctly |
| **Note:** If they consistently have $u$ horizontal and $2u$ vertically, then mark as a misread: M1A0M1A0M1A1 | | |
| **Total: 6 marks** | | |

---

## Question 7(b):

| Answer/Working | Mark | Guidance Notes |
|---|---|---|
| $v^2 = (7\sqrt{17})^2 - 28^2$ | M1 | Form an equation in $v$ only ($v$ is vertical component) |
| $\Rightarrow v = 7$ (or $-7$) | A1 | Second value not needed |
| Use of *suvat* to find the required time. Check logic: time speed is $< 7\sqrt{17}$ or time speed is $> 7\sqrt{17}$? | DM1 | Dependent on the first M mark. Complete method to obtain the required time, condone sign errors |
| $7 = 14 - gt \Rightarrow t = \frac{5}{7} = 0.71\ldots$ | A1 | Obtain a relevant value of $t$ |
| Total time $= 2 \times \frac{5}{7} = 1.4$ or $1.43$ (s) | A1 | For the required time to 2 sf or 3 sf. A0 for $\frac{10}{7}$; follows the use of an approximate value for $g$ |
| **Total: 5 marks** | | |

### Question 7(b) Alternative 1:

| Answer/Working | Mark | Guidance Notes |
|---|---|---|
| $\frac{1}{2}m(28^2 + 14^2) - \frac{1}{2}m(7\sqrt{17})^2 = mgh$ | M1 | Form an equation in $h$ only |
| $\Rightarrow h = 7.5$ | A1 | Correct only |
| Use of *suvat*; check logic: time speed is $< 7\sqrt{17}$ or time speed is $> 7\sqrt{17}$? | DM1 | Dependent on the first M mark. Complete method to obtain the required time, condone sign errors |
| $7.5 = 14t - \frac{1}{2} \times 9.8t^2 \Rightarrow t = \frac{5}{7},\ t = \frac{15}{7}$ | A1 | Obtain at least one relevant value of $t$ |
| Total time $= \frac{20}{7} - \left(\frac{15}{7} - \frac{5}{7}\right) = 1.4$ or $1.43$ (s) | A1 | For the required time to 2 sf or 3 sf. A0 for $\frac{10}{7}$; follows the use of an approximate value for $g$ |

### Question 7(b) Alternative 2:

| Answer/Working | Mark | Guidance Notes |
|---|---|---|
| Use $7\sqrt{17}$ to form an equation in $t$ only | M1 | |
| $\Rightarrow 7\sqrt{17} = \sqrt{(14 - gt)^2 + 28^2}$ | A1 | Or equivalent |
| Solve to find the required time; check logic: time speed is $< 7\sqrt{17}$ or time speed is $> 7\sqrt{17}$? | DM1 | Dependent on the first M mark. Complete method to obtain the required time, condone sign errors |
| $147 = 2gt - g^2t^2 \Rightarrow t = \frac{5}{7},\ t = \frac{15}{7}$ | A1 | Obtain at least one relevant value of $t$ |
| Total time $= \frac{20}{7} - \left(\frac{15}{7} - \frac{5}{7}\right) = 1.4$ or $1.43$ (s) | A1 | For the required time to 2 sf or 3 sf. A0 for $\frac{10}{7}$; follows the use of an approximate value for $g$ |
| **Total: 5 marks** | | |

The image appears to be essentially blank, containing only the "PMT" watermark in the top right corner and the Pearson Education Limited copyright notice at the bottom. There is no mark scheme content visible on this page to extract.
\begin{enumerate}
  \item \hspace{0pt} [In this question, the unit vectors $\mathbf { i }$ and $\mathbf { j }$ are in a vertical plane, $\mathbf { i }$ being horizontal and j being vertically upwards.]
\end{enumerate}

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{b6e93edf-1b9f-4ea9-bb41-f46f380bc623-22_398_1438_420_267}
\captionsetup{labelformat=empty}
\caption{Figure 3}
\end{center}
\end{figure}

A golf ball is hit from a point $O$ on horizontal ground and is modelled as a particle moving freely under gravity. The initial velocity of the ball is $( 2 u \mathbf { i } + u \mathbf { j } ) \mathrm { ms } ^ { - 1 }$ The ball first hits the horizontal ground at a point which is 80 m from $O$, as shown in Figure 3.

Use the model to\\
(a) show that $u = 14$\\
(b) find the total time, while the ball is in the air, for which the speed of the ball is greater than $7 \sqrt { 17 } \mathrm {~m} \mathrm {~s} ^ { - 1 }$

\hfill \mbox{\textit{Edexcel M2 2024 Q7 [11]}}