| Exam Board | CAIE |
|---|---|
| Module | M1 (Mechanics 1) |
| Year | 2020 |
| Session | Specimen |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Power and driving force |
| Type | Find steady/maximum speed given power |
| Difficulty | Moderate -0.8 This is a straightforward two-part work-energy-power question requiring only standard formulas (Power = Force × velocity, resolving forces on an incline). Part (a) involves direct substitution into P = Fv, while part (b) requires resolving forces parallel to the incline and using the constant speed condition. Both are routine textbook exercises with no problem-solving insight needed, making this easier than average. |
| Spec | 6.02l Power and velocity: P = Fv6.02m Variable force power: using scalar product |
| Answer | Marks | Guidance |
|---|---|---|
| 2(a) | \([DF] = \text{Power} = [350] \times 32 = 43.2\text{W}\) | M1 |
| 2(b) | \(DF = 1500 + 1200 \times 30 = 0\) \([DF] = 750\) | M1 M1 A1 |
**2(a)** | $[DF] = \text{Power} = [350] \times 32 = 43.2\text{W}$ | M1 |
**2(b)** | $DF = 1500 + 1200 \times 30 = 0$ $[DF] = 750$ | M1 M1 A1 | For using $DF = \text{inter}(750)\times y$ $v = 42 \text{m}^{-1}$ |
---2 A constant resistance of magnitude 1350 N acts on a car of mass 1200 kg .\\
(a) The car is moving along a straight level road at a constant speed of $32 \mathrm {~m} \mathrm {~s} ^ { - 1 }$.
Find, in kW , the rate at which the engine of the car is working.\\
(b) The car travels at a constant speed down a hill inclined at an angle of $\theta ^ { \circ }$ to the horizontal, where $\sin \theta ^ { \circ } = \frac { 1 } { 20 }$, with the engine working at 31.5 kW .
Find the speed of the car.\\
\hfill \mbox{\textit{CAIE M1 2020 Q2 [5]}}