| Exam Board | CAIE |
|---|---|
| Module | M1 (Mechanics 1) |
| Year | 2020 |
| Session | June |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Forces, equilibrium and resultants |
| Type | Power of engine at given speed |
| Difficulty | Moderate -0.8 This is a straightforward mechanics problem requiring standard application of Newton's second law and the power formula P=Fv. Part (a) involves isolating the trailer to find tension (F=ma with one resistance force), and part (b) requires finding the driving force on the whole system then calculating power. Both parts are routine textbook exercises with clear methods and minimal problem-solving insight required. |
| Spec | 3.03c Newton's second law: F=ma one dimension6.02l Power and velocity: P = Fv |
| Answer | Marks | Guidance |
|---|---|---|
| 2(a) | [T – 100 = 400 × 1.5] | M1 |
| T = 700 N | A1 |
| Answer | Marks |
|---|---|
| 2(b) | F – 250 – 100 = 2200 × 1.5 (F = 3650 N) |
| (M1 for using Newton’s second law for the system or for the car using the result from 2(a)) | M1 |
| For use of power =Fv | M1 |
| 73 000 W or 73 kW | A1 |
| Answer | Marks | Guidance |
|---|---|---|
| Question | Answer | Marks |
Question 2:
--- 2(a) ---
2(a) | [T – 100 = 400 × 1.5] | M1
T = 700 N | A1
2
--- 2(b) ---
2(b) | F – 250 – 100 = 2200 × 1.5 (F = 3650 N)
(M1 for using Newton’s second law for the system or for the car using the result from 2(a)) | M1
For use of power =Fv | M1
73 000 W or 73 kW | A1
3
Question | Answer | MarksA car of mass $1800\text{ kg}$ is towing a trailer of mass $400\text{ kg}$ along a straight horizontal road. The car and trailer are connected by a light rigid tow-bar. The car is accelerating at $1.5\text{ m s}^{-2}$. There are constant resistance forces of $250\text{ N}$ on the car and $100\text{ N}$ on the trailer.
\begin{enumerate}[label=(\alph*)]
\item Find the tension in the tow-bar. [2]
\item Find the power of the engine of the car at the instant when the speed is $20\text{ m s}^{-1}$. [3]
\end{enumerate}
\hfill \mbox{\textit{CAIE M1 2020 Q2 [5]}}