Edexcel M1 — Question 5

Exam BoardEdexcel
ModuleM1 (Mechanics 1)
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPulley systems
TypeParticle on rough horizontal surface, particle hanging
DifficultyStandard +0.3 This is a standard M1 pulley system problem requiring kinematics to find acceleration, then Newton's second law for two connected particles, and finally friction calculation. It follows a well-established template with straightforward multi-step application of familiar techniques, making it slightly easier than the average A-level question.
Spec3.02d Constant acceleration: SUVAT formulae3.03k Connected particles: pulleys and equilibrium3.03l Newton's third law: extend to situations requiring force resolution3.03o Advanced connected particles: and pulleys

5. Figure 4 \includegraphics[max width=\textwidth, alt={}, center]{94d9432d-1723-4549-ad5e-d4be0f5fd083-009_609_1026_301_516} A block of wood \(A\) of mass 0.5 kg rests on a rough horizontal table and is attached to one end of a light inextensible string. The string passes over a small smooth pulley \(P\) fixed at the edge of the table. The other end of the string is attached to a ball \(B\) of mass 0.8 kg which hangs freely below the pulley, as shown in Figure 4. The coefficient of friction between \(A\) and the table is \(\mu\). The system is released from rest with the string taut. After release, \(B\) descends a distance of 0.4 m in 0.5 s . Modelling \(A\) and \(B\) as particles, calculate
  1. the acceleration of \(B\),
  2. the tension in the string,
  3. the value of \(\mu\).
  4. State how in your calculations you have used the information that the string is inextensible.

Question 5:
Part (a)
AnswerMarks Guidance
Answer/WorkingMarks Guidance
Trapezium shape starting at origin, ending on \(t\)-axisB1 Trapezium starting at origin and ending on \(t\)-axis
Figures: \(22\) on speed axis; \(30\), \(30+T\), \(120\) on time axisB1 Allow missing \(0\) and a delineator oe for \(T\); allow if \(T=75\) used correctly on graph
Part (b)
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\(\frac{(120+T)22}{2} = 2145\)M1 A1 Equation in \(T\) only; equating area of trapezium to 2145 with correct number of terms; if single trapezium, must see evidence of \(\frac{1}{2}\) × sum of parallel sides
\(T = 75\)A1 N.B. Use of single suvat equation \(s = t(u+v)/2\) for whole motion is M0
Part (c)
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\(\frac{(t + t - 30)22}{2} = 990\)M1 A1 Equation in \(t\) only (may use \((t-30)\) as variable); equating area of trapezium to 990; use of motorcycle motion is M0; use of \(v=22\) for motorcycle is M0
\(t = 60\)A1 Allow \(30 + 30\)
Answer \(= 60 - 10 = 50\)A1
Part (d)
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\(990 = 0.5a \cdot 50^2\)M1 Equation in \(a\) only
\(a = 0.79,\ 0.792,\ \frac{99}{125}\) oeA1 N.B. Use of \(v=22\) for motorcycle is M0
## Question 5:

### Part (a)
| Answer/Working | Marks | Guidance |
|---|---|---|
| Trapezium shape starting at origin, ending on $t$-axis | B1 | Trapezium starting at origin and ending on $t$-axis |
| Figures: $22$ on speed axis; $30$, $30+T$, $120$ on time axis | B1 | Allow missing $0$ and a delineator oe for $T$; allow if $T=75$ used correctly on graph |

### Part (b)
| Answer/Working | Marks | Guidance |
|---|---|---|
| $\frac{(120+T)22}{2} = 2145$ | M1 A1 | Equation in $T$ only; equating area of trapezium to 2145 with correct number of terms; if single trapezium, must see evidence of $\frac{1}{2}$ × sum of parallel sides |
| $T = 75$ | A1 | N.B. Use of single suvat equation $s = t(u+v)/2$ for whole motion is M0 |

### Part (c)
| Answer/Working | Marks | Guidance |
|---|---|---|
| $\frac{(t + t - 30)22}{2} = 990$ | M1 A1 | Equation in $t$ only (may use $(t-30)$ as variable); equating area of trapezium to 990; use of motorcycle motion is M0; use of $v=22$ for motorcycle is M0 |
| $t = 60$ | A1 | Allow $30 + 30$ |
| Answer $= 60 - 10 = 50$ | A1 | |

### Part (d)
| Answer/Working | Marks | Guidance |
|---|---|---|
| $990 = 0.5a \cdot 50^2$ | M1 | Equation in $a$ only |
| $a = 0.79,\ 0.792,\ \frac{99}{125}$ oe | A1 | N.B. Use of $v=22$ for motorcycle is M0 |

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5.

Figure 4\\
\includegraphics[max width=\textwidth, alt={}, center]{94d9432d-1723-4549-ad5e-d4be0f5fd083-009_609_1026_301_516}

A block of wood $A$ of mass 0.5 kg rests on a rough horizontal table and is attached to one end of a light inextensible string. The string passes over a small smooth pulley $P$ fixed at the edge of the table. The other end of the string is attached to a ball $B$ of mass 0.8 kg which hangs freely below the pulley, as shown in Figure 4. The coefficient of friction between $A$ and the table is $\mu$. The system is released from rest with the string taut. After release, $B$ descends a distance of 0.4 m in 0.5 s . Modelling $A$ and $B$ as particles, calculate
\begin{enumerate}[label=(\alph*)]
\item the acceleration of $B$,
\item the tension in the string,
\item the value of $\mu$.
\item State how in your calculations you have used the information that the string is inextensible.
\end{enumerate}

\hfill \mbox{\textit{Edexcel M1  Q5}}