CAIE M1 2018 June — Question 6 9 marks

Exam BoardCAIE
ModuleM1 (Mechanics 1)
Year2018
SessionJune
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicWork done and energy
TypeResistance as kv - finding constant k
DifficultyStandard +0.3 This is a straightforward M1 mechanics question on power, force and motion. Part (i) uses P=Fv at terminal velocity where driving force equals resistance. Part (ii) applies F=ma with known maximum power. Part (iii) involves resolving forces on an incline with constant speed. All parts follow standard procedures with no novel problem-solving required, making it slightly easier than average.
Spec3.03c Newton's second law: F=ma one dimension6.02b Calculate work: constant force, resolved component6.02l Power and velocity: P = Fv

A car of mass \(1400\text{ kg}\) travelling at a speed of \(v\text{ m s}^{-1}\) experiences a resistive force of magnitude \(40v\text{ N}\). The greatest possible constant speed of the car along a straight level road is \(56\text{ m s}^{-1}\).
  1. Find, in kW, the greatest possible power of the car's engine. [2]
  2. Find the greatest possible acceleration of the car at an instant when its speed on a straight level road is \(32\text{ m s}^{-1}\). [3]
  3. The car travels down a hill inclined at an angle of \(\theta°\) to the horizontal at a constant speed of \(50\text{ m s}^{-1}\). The power of the car's engine is \(60\text{ kW}\). Find the value of \(\theta\). [4]

Question 6:

AnswerMarks
6(i)P
[ =40×56]
AnswerMarks Guidance
56M1 Power
For equating to Resistance, or equivalent
Velocity
AnswerMarks
Power is 125 (kW)A1
Total:2

AnswerMarks
6(ii)125440
Driving force is
AnswerMarks Guidance
32B1ft Follow through their power from (i)
125440
[ −40×32=1400a]
AnswerMarks Guidance
32M1 For 3-term Newton II equation
a=1.89(ms−2)A1
Total:3
QuestionAnswer Marks

AnswerMarks
6(iii)60000
[ +1400gsinθ−40×50=0]
AnswerMarks Guidance
50M1 For 3-term Newton II equation
A1Correct equation
800
[sinθ°= ]
AnswerMarks Guidance
14000M1
θ=3.3A1
Total:4
QuestionAnswer Marks
Question 6:
--- 6(i) ---
6(i) | P
[ =40×56]
56 | M1 | Power
For equating to Resistance, or equivalent
Velocity
Power is 125 (kW) | A1
Total: | 2
--- 6(ii) ---
6(ii) | 125440
Driving force is
32 | B1ft | Follow through their power from (i)
125440
[ −40×32=1400a]
32 | M1 | For 3-term Newton II equation
a=1.89(ms−2) | A1
Total: | 3
Question | Answer | Marks | Guidance
--- 6(iii) ---
6(iii) | 60000
[ +1400gsinθ−40×50=0]
50 | M1 | For 3-term Newton II equation
A1 | Correct equation
800
[sinθ°= ]
14000 | M1
θ=3.3 | A1
Total: | 4
Question | Answer | Marks | Guidance
A car of mass $1400\text{ kg}$ travelling at a speed of $v\text{ m s}^{-1}$ experiences a resistive force of magnitude $40v\text{ N}$. The greatest possible constant speed of the car along a straight level road is $56\text{ m s}^{-1}$.

\begin{enumerate}[label=(\roman*)]
\item Find, in kW, the greatest possible power of the car's engine. [2]

\item Find the greatest possible acceleration of the car at an instant when its speed on a straight level road is $32\text{ m s}^{-1}$. [3]

\item The car travels down a hill inclined at an angle of $\theta°$ to the horizontal at a constant speed of $50\text{ m s}^{-1}$. The power of the car's engine is $60\text{ kW}$. Find the value of $\theta$. [4]
\end{enumerate}

\hfill \mbox{\textit{CAIE M1 2018 Q6 [9]}}