CAIE M2 2013 November — Question 3 8 marks

Exam BoardCAIE
ModuleM2 (Mechanics 2)
Year2013
SessionNovember
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCircular Motion 1
TypeParticle on cone surface – no string (normal reaction only)
DifficultyStandard +0.3 This is a standard circular motion problem requiring resolution of forces in two directions (horizontal for centripetal force, vertical for equilibrium) and basic trigonometry. The setup is clearly defined, the method is routine for M2 students, and the algebraic manipulation to reach the given result is straightforward. Slightly easier than average due to being a well-practiced scenario with a clear path to solution.
Spec3.03p Resultant forces: using vectors6.05c Horizontal circles: conical pendulum, banked tracks

\includegraphics{figure_3} A particle moves on the inner surface of a smooth hollow cone of semi-vertical angle \(\alpha\). The axis of the cone is vertical with the vertex at the bottom. The particle moves in a horizontal circle of radius \(r\) with constant speed \(v\). Find expressions for the normal reactions on the particle from the cone surface, and show that the height of the particle above the vertex is \(\frac{v^2}{g \tan \alpha}\). [8]

Question 3:
AnswerMarks
3θ
Rcos = 0.5 g (=5)
Rsin θ = 0.5 × 5 2 × 0.4 (= 5)
tan θ =(0.5 × 5 2 × 0.4)/(0.5 g)
θ o
= 45 AG
R = 0.5 g/cos45
AnswerMarks
R = 7.07 NB1
M1
M1
A1
M1
AnswerMarks Guidance
A1[6] Resolving vertically
Use of N2L horizontally with
n w2r
acc =
Eliminating R
R 2 = (0.5 × 5 2 × 0.4) 2 + (0.5 g) 2
AnswerMarks
7.071..6
Question 3:
3 | θ
Rcos = 0.5 g (=5)
Rsin θ = 0.5 × 5 2 × 0.4 (= 5)
tan θ =(0.5 × 5 2 × 0.4)/(0.5 g)
θ o
= 45 AG
R = 0.5 g/cos45
R = 7.07 N | B1
M1
M1
A1
M1
A1 | [6] | Resolving vertically
Use of N2L horizontally with
n w2r
acc =
Eliminating R
R 2 = (0.5 × 5 2 × 0.4) 2 + (0.5 g) 2
7.071.. | 6
\includegraphics{figure_3}

A particle moves on the inner surface of a smooth hollow cone of semi-vertical angle $\alpha$. The axis of the cone is vertical with the vertex at the bottom. The particle moves in a horizontal circle of radius $r$ with constant speed $v$.

Find expressions for the normal reactions on the particle from the cone surface, and show that the height of the particle above the vertex is $\frac{v^2}{g \tan \alpha}$.
[8]

\hfill \mbox{\textit{CAIE M2 2013 Q3 [8]}}