CAIE M2 2006 June — Question 3 6 marks

Exam BoardCAIE
ModuleM2 (Mechanics 2)
Year2006
SessionJune
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCircular Motion 1
TypeConical pendulum – horizontal circle in free space (no surface)
DifficultyModerate -0.3 This is a standard conical pendulum problem requiring resolution of forces (tension and weight) and application of circular motion equations (v = rω). It involves straightforward trigonometry and algebraic manipulation with all necessary information provided, making it slightly easier than average but still requiring proper method and multiple steps.
Spec6.05a Angular velocity: definitions6.05c Horizontal circles: conical pendulum, banked tracks

3 \includegraphics[max width=\textwidth, alt={}, center]{ece63d46-5e56-4668-939a-9dbbcfc1a77a-3_437_567_269_788} A particle \(P\) of mass \(m \mathrm {~kg}\) is attached to one end of a light inextensible string of length \(L \mathrm {~m}\). The other end of the string is attached to a fixed point \(O\). The particle \(P\) moves with constant speed in a horizontal circle, with the string taut and inclined at \(35 ^ { \circ }\) to the vertical. \(O P\) rotates with angular speed \(2.2 \mathrm { rad } \mathrm { s } ^ { - 1 }\) about the vertical axis through \(O\) (see diagram). Find
  1. the value of \(L\),
  2. the speed of \(P\) in \(\mathrm { m } \mathrm { s } ^ { - 1 }\).

AnswerMarks Guidance
(i) \(T \cos 35° = mg\)B1, M1 For using Newton's second law and \(a = r\omega^2\)
\(T \sin 35° = m(L \sin 35°) \times 2^2\)
AnswerMarks
\(L = 2.52\)A1, A1, 4
\(v = 2.2(2.52\sin 35°)\)
AnswerMarks Guidance
Speed is 3.18 m s\(^{-1}\)M1, A1 ⊞ 2
**(i)** $T \cos 35° = mg$ | B1, M1 | For using Newton's second law and $a = r\omega^2$

$T \sin 35° = m(L \sin 35°) \times 2^2$
$L = 2.52$ | A1, A1, 4 | 

$v = 2.2(2.52\sin 35°)$
Speed is 3.18 m s$^{-1}$ | M1, A1 ⊞ | 2 | For using $v = \omega r$

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\includegraphics[max width=\textwidth, alt={}, center]{ece63d46-5e56-4668-939a-9dbbcfc1a77a-3_437_567_269_788}

A particle $P$ of mass $m \mathrm {~kg}$ is attached to one end of a light inextensible string of length $L \mathrm {~m}$. The other end of the string is attached to a fixed point $O$. The particle $P$ moves with constant speed in a horizontal circle, with the string taut and inclined at $35 ^ { \circ }$ to the vertical. $O P$ rotates with angular speed $2.2 \mathrm { rad } \mathrm { s } ^ { - 1 }$ about the vertical axis through $O$ (see diagram). Find\\
(i) the value of $L$,\\
(ii) the speed of $P$ in $\mathrm { m } \mathrm { s } ^ { - 1 }$.

\hfill \mbox{\textit{CAIE M2 2006 Q3 [6]}}