| Exam Board | OCR MEI |
|---|---|
| Module | M1 (Mechanics 1) |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Newton's laws and connected particles |
| Type | Two connected particles, horizontal surface |
| Difficulty | Standard +0.3 This is a straightforward connected particles problem requiring application of Newton's second law to the system and individual blocks. Students must consider two cases (acceleration left or right) and solve simultaneous equations, but the method is standard M1 fare with no conceptual surprises or complex problem-solving required. |
| Spec | 3.03d Newton's second law: 2D vectors3.03k Connected particles: pulleys and equilibrium3.03o Advanced connected particles: and pulleys |
| Answer | Marks | Guidance |
|---|---|---|
| Answer | Mark | Guidance |
| If the acceleration is to the right: Overall \(30 - F = (4 + 6) \times 2\) | M1 | Newton's 2nd Law in one direction. No extra forces allowed and signs must be correct |
| \(F = 10\) | A1 | |
| If the acceleration is to the left | M1 | For considering second direction. No extra forces allowed and signs must be correct |
| \(F = 50\) | A1 |
| Answer | Marks | Guidance |
|---|---|---|
| Answer | Mark | Guidance |
| 6 kg block: \(30 - T = 6 \times 2\) | M1 | Newton's 2nd law with correct elements on either block |
| \(T = 18\) | A1 | CAO. No follow through from part (i) |
| In the other case \(T = 42\) | A1 | CAO. No follow through from part (i) |
## Question 4:
### Part (i)
| Answer | Mark | Guidance |
|--------|------|----------|
| If the acceleration is to the right: Overall $30 - F = (4 + 6) \times 2$ | M1 | Newton's 2nd Law in one direction. No extra forces allowed and signs must be correct |
| $F = 10$ | A1 | |
| If the acceleration is to the left | M1 | For considering second direction. No extra forces allowed and signs must be correct |
| $F = 50$ | A1 | |
### Part (ii)
| Answer | Mark | Guidance |
|--------|------|----------|
| 6 kg block: $30 - T = 6 \times 2$ | M1 | Newton's 2nd law with correct elements on either block |
| $T = 18$ | A1 | CAO. No follow through from part (i) |
| In the other case $T = 42$ | A1 | CAO. No follow through from part (i) |4 Fig. 5 shows blocks of mass 4 kg and 6 kg on a smooth horizontal table. They are connected by a light, inextensible string. As shown, a horizontal force $F \mathrm {~N}$ acts on the 4 kg block and a horizontal force of 30 N acts on the 6 kg block.
The magnitude of the acceleration of the system is $2 \mathrm {~ms} ^ { - 2 }$.
\begin{figure}[h]
\begin{center}
\includegraphics[alt={},max width=\textwidth]{9bff41e0-7be0-4932-ae50-a612abb3fe19-4_119_1108_588_513}
\captionsetup{labelformat=empty}
\caption{Fig. 5}
\end{center}
\end{figure}
(i) Find the two possible values of $F$.\\
(ii) Find the tension in the string in each case.
\hfill \mbox{\textit{OCR MEI M1 Q4 [7]}}