Edexcel M5 2013 June — Question 5 10 marks

Exam BoardEdexcel
ModuleM5 (Mechanics 5)
Year2013
SessionJune
Marks10
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicMoments of inertia
TypeProve MI by integration
DifficultyChallenging +1.2 This is a standard M5 moment of inertia proof using integration with a given formula. While it requires setting up coordinates, integrating over the triangle using parallel rods, and applying the perpendicular axis theorem or parallel axis theorem, the approach is methodical and follows textbook procedures. The given rod formula significantly simplifies the work. Harder than routine C3 calculus but typical for Further Maths mechanics.
Spec6.04b Find centre of mass: using symmetry

5. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{90c52724-f7db-481f-acef-95a24f75b16a-07_561_545_205_705} \captionsetup{labelformat=empty} \caption{Figure 1}
\end{figure} A uniform triangular lamina \(A B C\), of mass \(M\), has \(A B = A C\) and \(B C = 2 a\). The mid-point of \(B C\) is \(D\) and \(A D = h\), as shown in Figure 1. Show, using integration, that the moment of inertia of the lamina about an axis through \(A\), perpendicular to the plane of the lamina, is $$\frac { M } { 6 } \left( a ^ { 2 } + 3 h ^ { 2 } \right)$$ [You may assume without proof that the moment of inertia of a uniform rod, of length \(2 l\) and mass \(m\), about an axis through its midpoint and perpendicular to the rod, is \(\frac { 1 } { 3 } m l ^ { 2 }\).]

I don't see any mark scheme content to clean up in your message. You've provided the question number "Question 5:" but no actual marking criteria, point allocations, or guidance notes that need to be formatted.
Please provide the extracted mark scheme content for Question 5, and I'll clean it up according to your specifications.
I don't see any mark scheme content to clean up in your message. You've provided the question number "Question 5:" but no actual marking criteria, point allocations, or guidance notes that need to be formatted.

Please provide the extracted mark scheme content for Question 5, and I'll clean it up according to your specifications.
5.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{90c52724-f7db-481f-acef-95a24f75b16a-07_561_545_205_705}
\captionsetup{labelformat=empty}
\caption{Figure 1}
\end{center}
\end{figure}

A uniform triangular lamina $A B C$, of mass $M$, has $A B = A C$ and $B C = 2 a$. The mid-point of $B C$ is $D$ and $A D = h$, as shown in Figure 1.

Show, using integration, that the moment of inertia of the lamina about an axis through $A$, perpendicular to the plane of the lamina, is

$$\frac { M } { 6 } \left( a ^ { 2 } + 3 h ^ { 2 } \right)$$

[You may assume without proof that the moment of inertia of a uniform rod, of length $2 l$ and mass $m$, about an axis through its midpoint and perpendicular to the rod, is $\frac { 1 } { 3 } m l ^ { 2 }$.]

\hfill \mbox{\textit{Edexcel M5 2013 Q5 [10]}}