| Exam Board | Edexcel |
|---|---|
| Module | M2 (Mechanics 2) |
| Year | 2017 |
| Session | October |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Impulse and momentum (advanced) |
| Type | Impulse from velocity change |
| Difficulty | Moderate -0.8 This is a straightforward application of the impulse-momentum theorem (impulse = change in momentum) with 2D vectors. Students need to find the change in velocity vector, multiply by mass, then find magnitude—all standard M2 techniques with no problem-solving insight required. The arithmetic is clean and the question is direct, making it easier than average. |
| Spec | 6.03e Impulse: by a force6.03f Impulse-momentum: relation |
| Answer | Marks | Guidance |
|---|---|---|
| Working/Answer | Marks | Notes |
| \(\mathbf{I} = 0.2(5\mathbf{i}+8\mathbf{j})-0.2(10\mathbf{i}-17\mathbf{j})\) | M1 | Use of \(\mathbf{I} = \pm m(\mathbf{v}-\mathbf{u})\). Must be using the change in velocity. |
| \(\mathbf{I} = -\mathbf{i}+5\mathbf{j}\) | A1 | Allow \(\pm\). Seen or implied. |
| \( | \mathbf{I} | = \sqrt{1+25} = \ldots\) |
| \(\ldots = \sqrt{26}\) (N s) | A1 | 5.099... 5.1 or better |
| Total: [4] |
# Question 1:
| Working/Answer | Marks | Notes |
|---|---|---|
| $\mathbf{I} = 0.2(5\mathbf{i}+8\mathbf{j})-0.2(10\mathbf{i}-17\mathbf{j})$ | M1 | Use of $\mathbf{I} = \pm m(\mathbf{v}-\mathbf{u})$. Must be using the change in velocity. |
| $\mathbf{I} = -\mathbf{i}+5\mathbf{j}$ | A1 | Allow $\pm$. Seen or implied. |
| $|\mathbf{I}| = \sqrt{1+25} = \ldots$ | M1 | Use of Pythagoras to find $|\mathbf{I}|$ or $|\mathbf{v}-\mathbf{u}|$ |
| $\ldots = \sqrt{26}$ (N s) | A1 | 5.099... 5.1 or better |
| **Total: [4]** | | |
---\begin{enumerate}
\item A small ball $B$ of mass 0.2 kg is hit by a bat. Immediately before being hit, $B$ has velocity $( 10 \mathbf { i } - 17 \mathbf { j } ) \mathrm { m } \mathrm { s } ^ { - 1 }$. Immediately after being hit, $B$ has velocity $( 5 \mathbf { i } + 8 \mathbf { j } ) \mathrm { ms } ^ { - 1 }$. Find the magnitude of the impulse exerted on $B$ by the bat.\\
(4)
\end{enumerate}
\hfill \mbox{\textit{Edexcel M2 2017 Q1 [4]}}