CAIE Further Paper 3 2021 November — Question 1 5 marks

Exam BoardCAIE
ModuleFurther Paper 3 (Further Paper 3)
Year2021
SessionNovember
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProjectiles
TypePerpendicular velocity directions
DifficultyModerate -0.8 This is a straightforward projectiles question requiring only standard SUVAT equations and basic vector perpendicularity. Parts (a) and (b) are routine bookwork applications, while part (c) is a simple algebraic deduction from the result in (b). The 5 marks total and minimal problem-solving demand place this well below average difficulty for Further Maths.
Spec1.10h Vectors in kinematics: uniform acceleration in vector form3.02i Projectile motion: constant acceleration model

A particle is projected with speed \(u\) at an angle \(\alpha\) above the horizontal from a point \(O\) on a horizontal plane. The particle moves freely under gravity.
  1. Write down the horizontal and vertical components of the velocity of the particle at time \(T\) after projection. [2] At time \(T\) after projection, the direction of motion of the particle is perpendicular to the direction of projection.
  2. Express \(T\) in terms of \(u\), \(g\) and \(\alpha\). [2]
  3. Deduce that \(T > \frac{u}{g}\). [1]

Question 1:

AnswerMarks Guidance
1(a)Velocity: →ucosα B1
↑usinα−gTB1 Allow 10 for g. Must be T.
2

AnswerMarks
1(b)ucosα sinα
=− oe
AnswerMarks Guidance
usinα−gT cosαM1 FT Allow missing minus sign on RHS for M1.
FT from (a).
u
T =
AnswerMarks
gsinαA1
2

AnswerMarks
1(c)u
sinα<1 giving T >
AnswerMarks Guidance
gB1 AG
1
AnswerMarks Guidance
QuestionAnswer Marks
Question 1:
--- 1(a) ---
1(a) | Velocity: →ucosα | B1
↑usinα−gT | B1 | Allow 10 for g. Must be T.
2
--- 1(b) ---
1(b) | ucosα sinα
=− oe
usinα−gT cosα | M1 FT | Allow missing minus sign on RHS for M1.
FT from (a).
u
T =
gsinα | A1
2
--- 1(c) ---
1(c) | u
sinα<1 giving T >
g | B1 | AG
1
Question | Answer | Marks | Guidance
A particle is projected with speed $u$ at an angle $\alpha$ above the horizontal from a point $O$ on a horizontal plane. The particle moves freely under gravity.

\begin{enumerate}[label=(\alph*)]
\item Write down the horizontal and vertical components of the velocity of the particle at time $T$ after projection. [2]

At time $T$ after projection, the direction of motion of the particle is perpendicular to the direction of projection.

\item Express $T$ in terms of $u$, $g$ and $\alpha$. [2]

\item Deduce that $T > \frac{u}{g}$. [1]
\end{enumerate}

\hfill \mbox{\textit{CAIE Further Paper 3 2021 Q1 [5]}}