OCR M1 — Question 2 6 marks

Exam BoardOCR
ModuleM1 (Mechanics 1)
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicForces, equilibrium and resultants
TypeResultant of coplanar forces
DifficultyModerate -0.3 This is a straightforward M1 mechanics question on resolving forces. Part (i) requires resolving the 6.5N force and using the perpendicularity condition to find θ (standard trigonometry), while part (ii) involves simple Pythagoras or resolution. The question is slightly easier than average because it's a standard two-force resultant problem with clear geometric constraints and the answer to part (i) is given, requiring only verification.
Spec3.03a Force: vector nature and diagrams3.03p Resultant forces: using vectors

\includegraphics{figure_2} Forces of magnitudes \(6.5\) N and \(2.5\) N act at a point in the directions shown. The resultant of the two forces has magnitude \(R\) N and acts at right angles to the force of magnitude \(2.5\) N (see diagram).
  1. Show that \(\theta = 22.6°\), correct to 3 significant figures. [3]
  2. Find the value of \(R\). [3]

\includegraphics{figure_2}

Forces of magnitudes $6.5$ N and $2.5$ N act at a point in the directions shown. The resultant of the two forces has magnitude $R$ N and acts at right angles to the force of magnitude $2.5$ N (see diagram).

\begin{enumerate}[label=(\roman*)]
\item Show that $\theta = 22.6°$, correct to 3 significant figures. [3]
\item Find the value of $R$. [3]
\end{enumerate}

\hfill \mbox{\textit{OCR M1  Q2 [6]}}