CAIE M2 2016 June — Question 5 9 marks

Exam BoardCAIE
ModuleM2 (Mechanics 2)
Year2016
SessionJune
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProjectiles
TypeProjection from elevated point - angle below horizontal or horizontal
DifficultyStandard +0.3 This is a standard projectile motion problem with downward projection requiring application of kinematic equations in two dimensions. While it involves solving simultaneous equations and working with components, the setup is straightforward with all given values clearly stated, and the methods are routine for M2 level. The multi-step nature and need to find both speed and angle elevates it slightly above average, but it remains a textbook-style question without requiring novel insight.
Spec3.02i Projectile motion: constant acceleration model

A particle is projected at an angle of \(θ°\) below the horizontal from a point at the top of a vertical cliff \(26 \text{ m}\) high. The particle strikes horizontal ground at a distance \(8 \text{ m}\) from the foot of the cliff \(2 \text{ s}\) after the instant of projection. Find
  1. the speed of projection of the particle and the value of \(θ\), [6]
  2. the direction of motion of the particle immediately before it strikes the ground. [3]

Question 5:

AnswerMarks
5 (i)vcosθ = 8/2
–26 = –2vsinθ – g22 /2
vsinθ = 3
v2 = (+/–3)2 + 42 or tanθ = 3/4
AnswerMarks
v = 5 ms−1B1
M1
A1
M1
AnswerMarks Guidance
A1Accept with sign errors
Page 5Mark Scheme Syllabus
Cambridge International A Level – May/June 20169709 51
QuAnswer Part
MarksMarks Notes
(ii)θ = 36.9
v = (+/–3) + 2g
v
tanα = v /(8/2)
v
Angle = 80.1 with the horizontal or angle
AnswerMarks
= 9.9 with the verticalA1
M1
M1
AnswerMarks
A16
3
6 (i) (a)
(i) (b)
AnswerMarks
(ii)2cos45 + 2 × 3/5 = 0.4ω2× 0.3
rads−1
ω = 4.67
R + 2sin45 + 2 × 4/5 = 0.4 g
R = 0.986 N
Tsin45 + T(4/5) = 0.4 g
T = 2.65
Tcos45 + T(3/5) = 0.4v2 /0.3
AnswerMarks
v = 1.61 ms−1M1
A1
A1
M1
A1
M1
A1
M1
AnswerMarks
A13
2
AnswerMarks
4Uses N2L with 2 components of T and
0.3ω2
accn =
2.654
7 (i)
(ii)
AnswerMarks
(iii)12(1.6–1.2)/1.2 = mgsin30
m = 0.8 kg
PE change = 1.6
IKE + 12 × 0.42 /2.4 =
1.6 × 0.2gsin30 + 12 × 0.22 /2.4
IKE = 1 J AG
12e/1.2 = 1.6 g sin30
e = 0.8
1.6v2 /2 + 12 × 0.82 /2.4 =
1.6g × 0.6sin30 + 12 × 0.22 /2.4
AnswerMarks
v = 1.5 ms−1M1
A1
B1
B1
M1
A1
M1
A1
M1
A1
AnswerMarks
A12
4
AnswerMarks
5Uses T = λext/l
2 × ans(i)
Both EE terms correct
KE/PE/EE balance
Both EE terms correct
λe × t/l = new weight component
May be stated without explanation
Must use new equilibrium position
Question 5:
--- 5 (i) ---
5 (i) | vcosθ = 8/2
–26 = –2vsinθ – g22 /2
vsinθ = 3
v2 = (+/–3)2 + 42 or tanθ = 3/4
v = 5 ms−1 | B1
M1
A1
M1
A1 | Accept with sign errors
Page 5 | Mark Scheme | Syllabus | Paper
Cambridge International A Level – May/June 2016 | 9709 | 51
Qu | Answer | Part
Marks | Marks | Notes
(ii) | θ = 36.9
v = (+/–3) + 2g
v
tanα = v /(8/2)
v
Angle = 80.1 with the horizontal or angle
= 9.9 with the vertical | A1
M1
M1
A1 | 6
3
6 (i) (a)
(i) (b)
(ii) | 2cos45 + 2 × 3/5 = 0.4ω2× 0.3
rads−1
ω = 4.67
R + 2sin45 + 2 × 4/5 = 0.4 g
R = 0.986 N
Tsin45 + T(4/5) = 0.4 g
T = 2.65
Tcos45 + T(3/5) = 0.4v2 /0.3
v = 1.61 ms−1 | M1
A1
A1
M1
A1
M1
A1
M1
A1 | 3
2
4 | Uses N2L with 2 components of T and
0.3ω2
accn =
2.654
7 (i)
(ii)
(iii) | 12(1.6–1.2)/1.2 = mgsin30
m = 0.8 kg
PE change = 1.6
IKE + 12 × 0.42 /2.4 =
1.6 × 0.2gsin30 + 12 × 0.22 /2.4
IKE = 1 J AG
12e/1.2 = 1.6 g sin30
e = 0.8
1.6v2 /2 + 12 × 0.82 /2.4 =
1.6g × 0.6sin30 + 12 × 0.22 /2.4
v = 1.5 ms−1 | M1
A1
B1
B1
M1
A1
M1
A1
M1
A1
A1 | 2
4
5 | Uses T = λext/l
2 × ans(i)
Both EE terms correct
KE/PE/EE balance
Both EE terms correct
λe × t/l = new weight component
May be stated without explanation
Must use new equilibrium position
A particle is projected at an angle of $θ°$ below the horizontal from a point at the top of a vertical cliff $26 \text{ m}$ high. The particle strikes horizontal ground at a distance $8 \text{ m}$ from the foot of the cliff $2 \text{ s}$ after the instant of projection. Find

\begin{enumerate}[label=(\roman*)]
\item the speed of projection of the particle and the value of $θ$, [6]
\item the direction of motion of the particle immediately before it strikes the ground. [3]
\end{enumerate}

\hfill \mbox{\textit{CAIE M2 2016 Q5 [9]}}