CAIE M2 2017 March — Question 3 7 marks

Exam BoardCAIE
ModuleM2 (Mechanics 2)
Year2017
SessionMarch
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProjectiles
TypeProjection from elevated point - angle below horizontal or horizontal
DifficultyModerate -0.3 This is a straightforward projectile motion problem with downward projection. Part (i) requires solving a quadratic equation using standard kinematic equations (s = ut + ½at²), and part (ii) involves finding horizontal and vertical velocity components then combining them. While it requires careful sign handling and multiple steps (7 marks total), the techniques are standard and well-practiced in M2, making it slightly easier than average but not trivial due to the computational work involved.
Spec3.02d Constant acceleration: SUVAT formulae3.02i Projectile motion: constant acceleration model

A particle \(P\) is projected with speed \(20 \text{ m s}^{-1}\) at an angle of \(60°\) below the horizontal, from a point \(O\) which is \(30 \text{ m}\) above horizontal ground.
  1. Calculate the time taken by \(P\) to reach the ground. [3]
  2. Calculate the speed and direction of motion of \(P\) immediately before it reaches the ground. [4]

Question 3:

AnswerMarks
3(i)1
30 = (20sin60)t + gt2
AnswerMarks Guidance
2M1 1
Uses s = ut + at2 vertically
2
AnswerMarks Guidance
5t2 + 10 3 t – 30 = 0M1 Sets up a quadratic equation and attempts
to solve it
AnswerMarks Guidance
t = 1.27A1
Total:3
QuestionAnswer Marks

AnswerMarks Guidance
3(ii)v2 = (20sin60)2 + 2g x 30 (hence v = 30) B1
V = 302 + (20cos60)2 or
AnswerMarks Guidance
tanθ = 30/(20cos60)M1
V = 31.6 ms–1A1
θ = 71.6° with the horizontalA1 Or 18.4° with the downward vertical
Total:4
QuestionAnswer Marks
Question 3:
--- 3(i) ---
3(i) | 1
30 = (20sin60)t + gt2
2 | M1 | 1
Uses s = ut + at2 vertically
2
5t2 + 10 3 t – 30 = 0 | M1 | Sets up a quadratic equation and attempts
to solve it
t = 1.27 | A1
Total: | 3
Question | Answer | Marks | Guidance
--- 3(ii) ---
3(ii) | v2 = (20sin60)2 + 2g x 30 (hence v = 30) | B1 | Uses v2 = u2 + 2as vertically
V = 302 + (20cos60)2 or
tanθ = 30/(20cos60) | M1
V = 31.6 ms–1 | A1
θ = 71.6° with the horizontal | A1 | Or 18.4° with the downward vertical
Total: | 4
Question | Answer | Marks | Guidance
A particle $P$ is projected with speed $20 \text{ m s}^{-1}$ at an angle of $60°$ below the horizontal, from a point $O$ which is $30 \text{ m}$ above horizontal ground.

\begin{enumerate}[label=(\roman*)]
\item Calculate the time taken by $P$ to reach the ground. [3]
\item Calculate the speed and direction of motion of $P$ immediately before it reaches the ground. [4]
\end{enumerate}

\hfill \mbox{\textit{CAIE M2 2017 Q3 [7]}}