CAIE M2 2018 June — Question 4 9 marks

Exam BoardCAIE
ModuleM2 (Mechanics 2)
Year2018
SessionJune
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProjectiles
TypeProjectile passing through given point
DifficultyModerate -0.3 This is a standard projectile motion question requiring routine application of kinematic equations at 45° (which simplifies calculations), followed by substitution to find V and solving a quadratic for two x-values. All steps are textbook exercises with no novel problem-solving required, making it slightly easier than average.
Spec3.02i Projectile motion: constant acceleration model

A small object is projected from a point \(O\) with speed \(V \text{ ms}^{-1}\) at an angle of \(45°\) above the horizontal. At time \(t\) after projection, the horizontal and vertically upwards displacements of the object from \(O\) are \(x \text{ m}\) and \(y \text{ m}\) respectively.
  1. Express \(x\) and \(y\) in terms of \(t\), and hence find the equation of the path. [4]
The object passes through the point with coordinates \((24, 18)\).
  1. Find \(V\). [2]
  2. The object passes through two points which are \(22.5 \text{ m}\) above the level of \(O\). Find the values of \(x\) for these points. [3]

Question 4:

AnswerMarks Guidance
4(i)x = (Vcos45)t B1
gt2
y = (Vsin45)t –
AnswerMarks Guidance
2B1 Use s=ut+ 1gt2 vertically
2
( )
Vsin45 x 1  x  2
y= − g
( )  
AnswerMarks Guidance
Vcos45 2 Vcos45M1 Attempt to eliminate t
10x2
y=x−
AnswerMarks
V2A1
4

AnswerMarks
4(ii)10×242
18=24−
AnswerMarks Guidance
V2M1 Substitutes x = 18, y = 24 in
part (i) equation
AnswerMarks
V = 31(.0)A1
2

AnswerMarks
4(iii)10x2
22.5=x−
AnswerMarks Guidance
960M1 Put y = 22.5 in part (i)
x2 −96x+2160=0M1 Attempt to solve a quadratic
equation
AnswerMarks
x = 36, 60A1
3
AnswerMarks Guidance
QuestionAnswer Marks
Question 4:
--- 4(i) ---
4(i) | x = (Vcos45)t | B1 | Use horizontal motion
gt2
y = (Vsin45)t –
2 | B1 | Use s=ut+ 1gt2 vertically
2
( )
Vsin45 x 1  x  2
y= − g
( )  
Vcos45 2 Vcos45 | M1 | Attempt to eliminate t
10x2
y=x−
V2 | A1
4
--- 4(ii) ---
4(ii) | 10×242
18=24−
V2 | M1 | Substitutes x = 18, y = 24 in
part (i) equation
V = 31(.0) | A1
2
--- 4(iii) ---
4(iii) | 10x2
22.5=x−
960 | M1 | Put y = 22.5 in part (i)
x2 −96x+2160=0 | M1 | Attempt to solve a quadratic
equation
x = 36, 60 | A1
3
Question | Answer | Marks | Guidance
A small object is projected from a point $O$ with speed $V \text{ ms}^{-1}$ at an angle of $45°$ above the horizontal. At time $t$ after projection, the horizontal and vertically upwards displacements of the object from $O$ are $x \text{ m}$ and $y \text{ m}$ respectively.

\begin{enumerate}[label=(\roman*)]
\item Express $x$ and $y$ in terms of $t$, and hence find the equation of the path. [4]
\end{enumerate}

The object passes through the point with coordinates $(24, 18)$.

\begin{enumerate}[label=(\roman*)]
\setcounter{enumi}{1}
\item Find $V$. [2]
\item The object passes through two points which are $22.5 \text{ m}$ above the level of $O$. Find the values of $x$ for these points. [3]
\end{enumerate}

\hfill \mbox{\textit{CAIE M2 2018 Q4 [9]}}