CAIE M2 2006 November — Question 1 4 marks

Exam BoardCAIE
ModuleM2 (Mechanics 2)
Year2006
SessionNovember
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProjectiles
TypeHorizontal projection from height
DifficultyModerate -0.8 This is a straightforward projectiles question requiring standard application of kinematic equations for horizontal projection. Part (i) involves deriving the trajectory equation by eliminating time from x=ut and y=-½gt², while part (ii) substitutes a given horizontal distance to find height. Both parts are routine textbook exercises with no problem-solving insight required, making this easier than average.
Spec3.02d Constant acceleration: SUVAT formulae3.02i Projectile motion: constant acceleration model

1 A stone is projected horizontally with speed \(8 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) from a point \(O\) at the top of a vertical cliff. The horizontal and vertically upward displacements of the stone from \(O\) are \(x \mathrm {~m}\) and \(y \mathrm {~m}\) respectively.
  1. Find the equation of the stone's trajectory. The stone enters the sea at a horizontal distance of 24 m from the base of the cliff.
  2. Find the height above sea level of the top of the cliff.

Question 1:
Part (i)
AnswerMarks Guidance
Answer/WorkingMark Guidance
\(y = \pm \dfrac{10x^2}{2 \times 8^2 \times 1^2}\)M1 For correct substitution into trajectory formula (in booklet)
or \(x = 8t\), \(y = \pm \frac{1}{2}gt^2\)M1 For an attempt to eliminate \(t\)
\(y = -\dfrac{5}{64}x^2\)A1 (2)
Part (ii)
AnswerMarks Guidance
Answer/WorkingMark Guidance
M1For using \(h = -y(24)\) or substituting \(t=3\) in \(y = \frac{1}{2}gt^2\)
Height \(= 45\)mA1 (2)
## Question 1:

### Part (i)
| Answer/Working | Mark | Guidance |
|---|---|---|
| $y = \pm \dfrac{10x^2}{2 \times 8^2 \times 1^2}$ | M1 | For correct substitution into trajectory formula (in booklet) |
| or $x = 8t$, $y = \pm \frac{1}{2}gt^2$ | M1 | For an attempt to eliminate $t$ |
| $y = -\dfrac{5}{64}x^2$ | A1 (2) | |

### Part (ii)
| Answer/Working | Mark | Guidance |
|---|---|---|
| | M1 | For using $h = -y(24)$ or substituting $t=3$ in $y = \frac{1}{2}gt^2$ |
| Height $= 45$m | A1 (2) | |

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1 A stone is projected horizontally with speed $8 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ from a point $O$ at the top of a vertical cliff. The horizontal and vertically upward displacements of the stone from $O$ are $x \mathrm {~m}$ and $y \mathrm {~m}$ respectively.\\
(i) Find the equation of the stone's trajectory.

The stone enters the sea at a horizontal distance of 24 m from the base of the cliff.\\
(ii) Find the height above sea level of the top of the cliff.

\hfill \mbox{\textit{CAIE M2 2006 Q1 [4]}}