| Exam Board | OCR |
|---|---|
| Module | M1 (Mechanics 1) |
| Year | 2009 |
| Session | January |
| Marks | 9 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Newton's laws and connected particles |
| Type | Car towing trailer, horizontal |
| Difficulty | Moderate -0.8 This is a straightforward connected particles problem requiring application of Newton's second law to two cases (constant speed and constant acceleration). The setup is standard, the calculations are routine (simple arithmetic with given values), and no problem-solving insight is needed—just systematic application of F=ma to each object separately. |
| Spec | 3.03c Newton's second law: F=ma one dimension3.03d Newton's second law: 2D vectors3.03k Connected particles: pulleys and equilibrium3.03l Newton's third law: extend to situations requiring force resolution3.03m Equilibrium: sum of resolved forces = 0 |
2 A trailer of mass 500 kg is attached to a car of mass 1250 kg by a light rigid horizontal tow-bar. The car and trailer are travelling along a horizontal straight road. The resistance to motion of the trailer is 400 N and the resistance to motion of the car is 900 N . Find both the tension in the tow-bar and the driving force of the car in each of the following cases.\\
(i) The car and trailer are travelling at constant speed.\\
(ii) The car and trailer have acceleration $0.6 \mathrm {~m} \mathrm {~s} ^ { - 2 }$.
\hfill \mbox{\textit{OCR M1 2009 Q2 [9]}}