Edexcel M2 2021 June — Question 6 15 marks

Exam BoardEdexcel
ModuleM2 (Mechanics 2)
Year2021
SessionJune
Marks15
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicAdvanced work-energy problems
TypeConnected particles pulley energy method
DifficultyStandard +0.3 This is a standard M2 connected particles problem using work-energy methods. While it has multiple parts and requires careful bookkeeping of energy changes, all techniques are routine: calculating PE changes using the given angle, finding friction work using coefficient and normal reaction, and applying work-energy principle twice. The setup is typical textbook fare with no novel insights required, making it slightly easier than average.
Spec3.03v Motion on rough surface: including inclined planes6.02a Work done: concept and definition6.02b Calculate work: constant force, resolved component6.02d Mechanical energy: KE and PE concepts6.02i Conservation of energy: mechanical energy principle

6. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{e6e37d85-f8de-490a-82a9-8a3c16e2fdd0-16_273_819_260_566} \captionsetup{labelformat=empty} \caption{Figure 4}
\end{figure} Two particles, \(A\) and \(B\), of mass 2 kg and 3 kg respectively, are connected by a light inextensible string. Particle \(A\) is held at rest at the point \(X\) on a fixed rough ramp that is inclined at an angle \(\theta\) to the horizontal, where \(\tan \theta = \frac { 5 } { 12 }\). The string passes over a small smooth pulley \(P\) that is fixed at the top of the ramp. Particle \(B\) hangs vertically below \(P\), 2 m above the ground, as shown in Figure 4. The particles are released from rest with the string taut so that \(A\) moves up the ramp and the section of the string from \(A\) to \(P\) is parallel to a line of greatest slope of the ramp. The coefficient of friction between \(A\) and the ramp is \(\frac { 3 } { 8 }\) Air resistance is ignored.
  1. Find the potential energy lost by the system as \(A\) moves 2 m up the ramp.
  2. Find the work done against friction as \(A\) moves 2 m up the ramp. When \(B\) hits the ground, \(B\) is brought to rest by the impact and does not rebound and \(A\) continues to move up the ramp.
  3. Use the work-energy principle to find the speed of \(B\) at the instant before it hits the ground. Particle \(A\) comes to instantaneous rest at the point \(Y\) on the ramp, where \(X Y = ( 2 + d ) \mathrm { m }\).
  4. Use the work-energy principle to find the value of \(d\).

6.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{e6e37d85-f8de-490a-82a9-8a3c16e2fdd0-16_273_819_260_566}
\captionsetup{labelformat=empty}
\caption{Figure 4}
\end{center}
\end{figure}

Two particles, $A$ and $B$, of mass 2 kg and 3 kg respectively, are connected by a light inextensible string. Particle $A$ is held at rest at the point $X$ on a fixed rough ramp that is inclined at an angle $\theta$ to the horizontal, where $\tan \theta = \frac { 5 } { 12 }$. The string passes over a small smooth pulley $P$ that is fixed at the top of the ramp. Particle $B$ hangs vertically below $P$, 2 m above the ground, as shown in Figure 4.

The particles are released from rest with the string taut so that $A$ moves up the ramp and the section of the string from $A$ to $P$ is parallel to a line of greatest slope of the ramp. The coefficient of friction between $A$ and the ramp is $\frac { 3 } { 8 }$

Air resistance is ignored.
\begin{enumerate}[label=(\alph*)]
\item Find the potential energy lost by the system as $A$ moves 2 m up the ramp.
\item Find the work done against friction as $A$ moves 2 m up the ramp.

When $B$ hits the ground, $B$ is brought to rest by the impact and does not rebound and $A$ continues to move up the ramp.
\item Use the work-energy principle to find the speed of $B$ at the instant before it hits the ground.

Particle $A$ comes to instantaneous rest at the point $Y$ on the ramp, where $X Y = ( 2 + d ) \mathrm { m }$.
\item Use the work-energy principle to find the value of $d$.
\end{enumerate}

\hfill \mbox{\textit{Edexcel M2 2021 Q6 [15]}}