CAIE M1 2010 June — Question 5 7 marks

Exam BoardCAIE
ModuleM1 (Mechanics 1)
Year2010
SessionJune
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicWork done and energy
TypeEnergy method - smooth inclined plane (no resistance)
DifficultyModerate -0.3 This is a straightforward energy conservation problem with standard mechanics. Part (i) requires simple application of KE = PE with no friction. Part (ii) adds work done against friction but still follows a direct energy accounting approach (initial KE = PE gained + work against friction). The calculations are routine and the problem structure is typical for M1 level, making it slightly easier than average A-level difficulty.
Spec6.02a Work done: concept and definition6.02e Calculate KE and PE: using formulae

\(P\) and \(Q\) are fixed points on a line of greatest slope of an inclined plane. The point \(Q\) is at a height of 0.45 m above the level of \(P\). A particle of mass 0.3 kg moves upwards along the line \(PQ\).
  1. Given that the plane is smooth and that the particle just reaches \(Q\), find the speed with which it passes through \(P\). [3]
  2. It is given instead that the plane is rough. The particle passes through \(P\) with the same speed as that found in part (i), and just reaches a point \(R\) which is between \(P\) and \(Q\). The work done against the frictional force in moving from \(P\) to \(R\) is 0.39 J. Find the potential energy gained by the particle in moving from \(P\) to \(R\) and hence find the height of \(R\) above the level of \(P\). [4]

AnswerMarks Guidance
(i)M1 For using KE loss = PE gain or \(0^2 = u^2 - 2(g\sin\alpha)(0.45/\sin\alpha)\)
\(\frac{1}{2}(m)u^2 = (m)g(0.45)\)A1
Speed is \(3 \text{ ms}^{-1}\)A1
[3]
(ii) \([PE \text{ gain} = \frac{1}{2}0.3 \times 3^2 = 0.39]\)M1 For using PE gain = KE lost − WD
PE gain is \(0.96 \text{ J}\)A1ft ft incorrect \(u\)
\([0.3gh = 0.96]\)DM1 For using PE = \(mgh\); dependent on the given WD being reflected in the value for PE used
R is \(0.32 \text{ m}\) higher than the level of PA1
[4]
**(i)** | M1 | For using KE loss = PE gain or $0^2 = u^2 - 2(g\sin\alpha)(0.45/\sin\alpha)$
$\frac{1}{2}(m)u^2 = (m)g(0.45)$ | A1 |
Speed is $3 \text{ ms}^{-1}$ | A1 |
| | | **[3]**

**(ii)** $[PE \text{ gain} = \frac{1}{2}0.3 \times 3^2 = 0.39]$ | M1 | For using PE gain = KE lost − WD
PE gain is $0.96 \text{ J}$ | A1ft | ft incorrect $u$
$[0.3gh = 0.96]$ | DM1 | For using PE = $mgh$; dependent on the given WD being reflected in the value for PE used
R is $0.32 \text{ m}$ higher than the level of P | A1 |
| | | **[4]**

---
$P$ and $Q$ are fixed points on a line of greatest slope of an inclined plane. The point $Q$ is at a height of 0.45 m above the level of $P$. A particle of mass 0.3 kg moves upwards along the line $PQ$.

\begin{enumerate}[label=(\roman*)]
\item Given that the plane is smooth and that the particle just reaches $Q$, find the speed with which it passes through $P$. [3]
\item It is given instead that the plane is rough. The particle passes through $P$ with the same speed as that found in part (i), and just reaches a point $R$ which is between $P$ and $Q$. The work done against the frictional force in moving from $P$ to $R$ is 0.39 J. Find the potential energy gained by the particle in moving from $P$ to $R$ and hence find the height of $R$ above the level of $P$. [4]
\end{enumerate}

\hfill \mbox{\textit{CAIE M1 2010 Q5 [7]}}