Edexcel M1 2009 June — Question 5 9 marks

Exam BoardEdexcel
ModuleM1 (Mechanics 1)
Year2009
SessionJune
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicFriction
TypeSingle angled force - find limiting friction or coefficient
DifficultyModerate -0.3 This is a standard M1 friction problem requiring resolution of forces in two directions and application of F=μR at limiting equilibrium. While it involves multiple steps (resolving horizontally and vertically, finding R, then P), the method is routine and well-practiced. The 9 marks reflect the working required rather than conceptual difficulty. Slightly easier than average due to being a textbook application of standard friction mechanics.
Spec3.03a Force: vector nature and diagrams3.03b Newton's first law: equilibrium3.03e Resolve forces: two dimensions3.03f Weight: W=mg3.03i Normal reaction force3.03r Friction: concept and vector form3.03t Coefficient of friction: F <= mu*R model3.03u Static equilibrium: on rough surfaces

\includegraphics{figure_1} A small box of mass 15 kg rests on a rough horizontal plane. The coefficient of friction between the box and the plane is 0.2. A force of magnitude \(P\) newtons is applied to the box at 50° to the horizontal, as shown in Figure 1. The box is on the point of sliding along the plane. Find the value of \(P\), giving your answer to 2 significant figures. [9]

AnswerMarks
\(F = P\cos 50°\)M1 A1
\(F = 0.2R\) seen or impliedB1
\(P\sin 50° + R = 15g\)M1 A1 A1
Eliminating \(R\); Solving for \(P\);DM1; D M1;
\(P = 37\) (2 SF)A1
Total: [9]
$F = P\cos 50°$ | M1 A1 |
$F = 0.2R$ seen or implied | B1 |
$P\sin 50° + R = 15g$ | M1 A1 A1 |
Eliminating $R$; Solving for $P$; | DM1; D M1; |
$P = 37$ (2 SF) | A1 |
| **Total: [9]** |
\includegraphics{figure_1}

A small box of mass 15 kg rests on a rough horizontal plane. The coefficient of friction between the box and the plane is 0.2. A force of magnitude $P$ newtons is applied to the box at 50° to the horizontal, as shown in Figure 1. The box is on the point of sliding along the plane.

Find the value of $P$, giving your answer to 2 significant figures. [9]

\hfill \mbox{\textit{Edexcel M1 2009 Q5 [9]}}