CAIE FP2 2017 June — Question 2 9 marks

Exam BoardCAIE
ModuleFP2 (Further Pure Mathematics 2)
Year2017
SessionJune
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicMomentum and Collisions 1
TypeDirect collision with direction reversal
DifficultyChallenging +1.2 This is a standard SHM problem requiring knowledge of the acceleration formula a = ω²x and integration to find the period. While it involves multiple steps and algebraic manipulation (finding OM from the ratio, then using calculus for the period), the techniques are routine for Further Maths students and follow predictable patterns without requiring novel insight or complex problem-solving strategies.
Spec4.10f Simple harmonic motion: x'' = -omega^2 x

A particle \(P\) moves on a straight line in simple harmonic motion. The centre of the motion is \(O\), and the amplitude of the motion is \(2.5\) m. The points \(L\) and \(M\) are on the line, on opposite sides of \(O\), with \(OL = 1.5\) m. The magnitudes of the accelerations of \(P\) at \(L\) and at \(M\) are in the ratio \(3 : 4\).
  1. Find the distance \(OM\). [2]
The time taken by \(P\) to travel directly from \(L\) to \(M\) is \(2\) s.
  1. Find the period of the motion. [5]
  2. Find the speed of \(P\) when it passes through \(L\). [2]

Question 2:

AnswerMarks Guidance
2(i)OL/OM = ¾, OM = 2 [m] M1 A1
Total:2

AnswerMarks
2(ii)EITHER:
ω t = sin–1 (OL/2⋅5) + sin–1(OM/2⋅5)
LM
or ω t = sin–1 (OL/2⋅5), ω (2 – t ) = sin–1 OM/2⋅5)
OL OL
AnswerMarks Guidance
so 2ω = sin–1 0⋅6 + sin–1 0⋅8 [= 0⋅6435 + 0⋅9273](*M1 A1) Find eqn. (AEF) for ω, for example using x = a sin ωt
OR:
ω t = cos–1 (–OM/2⋅5) – cos–1(OL/2⋅5)
LM
or ω t = cos–1 (OL/2⋅5), ω (2 + t ) = cos–1 (–OM/2⋅5)
AL AL
so 2ω = cos–1 (–0⋅8) – cos–1 0⋅6 [= 2⋅498 – 0⋅927]
AnswerMarks Guidance
or π – cos–1 0⋅8 – cos–1 0⋅6(*M1 A1) or x = a cos ωt
(A is at 2⋅5 from O, near L)
AnswerMarks Guidance
ω = π / 4 or 0⋅785 (M1 dep *M1)DM1 A1 Simplify to find ω (may be implied by T)
T = 2π / ω = 8 [s]B1 FT Find period T (FT on ω)
Total:5
QuestionAnswer Marks

AnswerMarks Guidance
2(iii)v = ω√(2⋅52 – 1⋅52) = 2ω = π / 2 or 1⋅57 [m s–1]
LM1 A1 Find speed v at L
L
AnswerMarks
Total:2
Question 2:
--- 2(i) ---
2(i) | OL/OM = ¾, OM = 2 [m] | M1 A1 | Find OM by equating ratios of distances and acceln.
Total: | 2
--- 2(ii) ---
2(ii) | EITHER:
ω t = sin–1 (OL/2⋅5) + sin–1(OM/2⋅5)
LM
or ω t = sin–1 (OL/2⋅5), ω (2 – t ) = sin–1 OM/2⋅5)
OL OL
so 2ω = sin–1 0⋅6 + sin–1 0⋅8 [= 0⋅6435 + 0⋅9273] | (*M1 A1) | Find eqn. (AEF) for ω, for example using x = a sin ωt
OR:
ω t = cos–1 (–OM/2⋅5) – cos–1(OL/2⋅5)
LM
or ω t = cos–1 (OL/2⋅5), ω (2 + t ) = cos–1 (–OM/2⋅5)
AL AL
so 2ω = cos–1 (–0⋅8) – cos–1 0⋅6 [= 2⋅498 – 0⋅927]
or π – cos–1 0⋅8 – cos–1 0⋅6 | (*M1 A1) | or x = a cos ωt
(A is at 2⋅5 from O, near L)
ω = π / 4 or 0⋅785 (M1 dep *M1) | DM1 A1 | Simplify to find ω (may be implied by T)
T = 2π / ω = 8 [s] | B1 FT | Find period T (FT on ω)
Total: | 5
Question | Answer | Marks | Guidance
--- 2(iii) ---
2(iii) | v = ω√(2⋅52 – 1⋅52) = 2ω = π / 2 or 1⋅57 [m s–1]
L | M1 A1 | Find speed v at L
L
Total: | 2
A particle $P$ moves on a straight line in simple harmonic motion. The centre of the motion is $O$, and the amplitude of the motion is $2.5$ m. The points $L$ and $M$ are on the line, on opposite sides of $O$, with $OL = 1.5$ m. The magnitudes of the accelerations of $P$ at $L$ and at $M$ are in the ratio $3 : 4$.

\begin{enumerate}[label=(\roman*)]
\item Find the distance $OM$. [2]
\end{enumerate}

The time taken by $P$ to travel directly from $L$ to $M$ is $2$ s.

\begin{enumerate}[label=(\roman*)]
\setcounter{enumi}{1}
\item Find the period of the motion. [5]
\item Find the speed of $P$ when it passes through $L$. [2]
\end{enumerate}

\hfill \mbox{\textit{CAIE FP2 2017 Q2 [9]}}