CAIE Further Paper 3 2024 November — Question 7 4 marks

Exam BoardCAIE
ModuleFurther Paper 3 (Further Paper 3)
Year2024
SessionNovember
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProjectiles
TypeProjectile with bounce or impact
DifficultyChallenging +1.8 This is a challenging mechanics problem requiring understanding of projectile motion, oblique impacts, and coefficient of restitution. The key insight is recognizing that the velocity component perpendicular to the inclined plane before impact relates to the vertical rebound through the restitution equation. While it involves multiple concepts (projectiles, vector resolution, impacts), the mathematical steps are relatively standard once the setup is understood. The 4-mark allocation and 'show that' format indicate moderate difficulty within Further Maths, though the geometric reasoning about velocity components at an oblique impact elevates it above routine exercises.
Spec3.02i Projectile motion: constant acceleration model6.03k Newton's experimental law: direct impact

A particle \(P\) is projected with speed \(u\) at an angle \(\tan^{-1}\left(\frac{4}{3}\right)\) above the horizontal from a point \(O\) on a horizontal plane and moves freely under gravity. When \(P\) is moving horizontally, it strikes a smooth inclined plane at the point \(A\). This plane is inclined to the horizontal at an angle \(\alpha\), and the line of greatest slope through \(A\) lies in the vertical plane through \(O\) and \(A\). As a result of the impact, \(P\) moves vertically upwards. The coefficient of restitution between \(P\) and the inclined plane is \(e\).
  1. Show that \(e \tan^2 \alpha = 1\). [4]

Question 7:

AnswerMarks
7(a)When P strikes plane, velocity is →ucos,
3 3
Before impact: parallel to inclined plane ucos, perpendicular to plane usin
AnswerMarks Guidance
5 5M1 3
u
5
3 3
After impact: components ucos (parallel) and eusin (perpendicular)
AnswerMarks
5 5A1
3 3
Since velocity is vertical after impact, tan= ucos/ eusin
AnswerMarks Guidance
5 5M1
tan=1/etan, e tan2 =1A1 AG
4
AnswerMarks Guidance
QuestionAnswer Marks

AnswerMarks
7(b)(usin)2 8u2
Greatest height of P before impact: H = =
AnswerMarks Guidance
2g 25gM1A1 Note: alternative methods.
3
After impact, vertical speed of P is u (cos)2 +e2(sin)2
AnswerMarks
5M1
3
Use V2 =U2 +2as to greatest height, equal to H
16
9 ( ) 3
u2 (cos)2 +e2(sin)2 =2g H
AnswerMarks
25 16M1
1 e 1
Use part (a): tan= , cos= , sin=
e 1+e 1+e
AnswerMarks
Substitute to find eM1
1
3e2 +2e−1=0, e=
AnswerMarks
3A1
6
Question 7:
--- 7(a) ---
7(a) | When P strikes plane, velocity is →ucos,
3 3
Before impact: parallel to inclined plane ucos, perpendicular to plane usin
5 5 | M1 | 3
u
5
3 3
After impact: components ucos (parallel) and eusin (perpendicular)
5 5 | A1
3 3
Since velocity is vertical after impact, tan= ucos/ eusin
5 5 | M1
tan=1/etan, e tan2 =1 | A1 | AG
4
Question | Answer | Marks | Guidance
--- 7(b) ---
7(b) | (usin)2 8u2
Greatest height of P before impact: H = =
2g 25g | M1A1 | Note: alternative methods.
3
After impact, vertical speed of P is u (cos)2 +e2(sin)2
5 | M1
3
Use V2 =U2 +2as to greatest height, equal to H
16
9 ( ) 3
u2 (cos)2 +e2(sin)2 =2g H
25 16 | M1
1 e 1
Use part (a): tan= , cos= , sin=
e 1+e 1+e
Substitute to find e | M1
1
3e2 +2e−1=0, e=
3 | A1
6
A particle $P$ is projected with speed $u$ at an angle $\tan^{-1}\left(\frac{4}{3}\right)$ above the horizontal from a point $O$ on a horizontal plane and moves freely under gravity. When $P$ is moving horizontally, it strikes a smooth inclined plane at the point $A$. This plane is inclined to the horizontal at an angle $\alpha$, and the line of greatest slope through $A$ lies in the vertical plane through $O$ and $A$.

As a result of the impact, $P$ moves vertically upwards. The coefficient of restitution between $P$ and the inclined plane is $e$.

\begin{enumerate}[label=(\alph*)]
\item Show that $e \tan^2 \alpha = 1$. [4]
\end{enumerate}

\hfill \mbox{\textit{CAIE Further Paper 3 2024 Q7 [4]}}