A car of mass 2100kg tows a caravan of mass 900kg along a level road. The car's engine produces a force of 14kN. @ Calculate the acceleration of the car and the caravan. B Find the tension in the link between the car and caravan.

The car and caravan move together, so their masses combine.

$$M_{total} = m_{car} + m_{caravan}$$ $$M_{total} = 2100\, \text{kg} + 900\, \text{kg}$$ $$M_{total} = 3000\, \text{kg}$$

The force is given in kilonewtons (kN), so convert it to Newtons (N).

$$F_{engine} = 14\, \text{kN} = 14 \times 1000\, \text{N}$$ $$F_{engine} = 14000\, \text{N}$$

Using the formula $F = ma$, where $F$ is the net force and $m$ is the total mass.

$$F_{engine} = M_{total} \times a$$ $$14000\, \text{N} = 3000\, \text{kg} \times a$$ $$a = \frac{14000\, \text{N}}{3000\, \text{kg}}$$ $$a = \frac{14}{3}\, \text{m/s}^2$$ $$a \approx 4.67\, \text{m/s}^2$$

The acceleration of the car and caravan is $\boxed{\text{4.67 m/s}^2}$.

The only horizontal force acting on the caravan is the tension ($T$) from the link, pulling it forward.
Using Newton's second law for the caravan: $T = m_{caravan} \times a$.

$$T = 900\, \text{kg} \times \frac{14}{3}\, \text{m/s}^2$$ $$T = 300 \times 14\, \text{N}$$ $$T = 4200\, \text{N}$$

The tension in the link is $\boxed{\text{4200 N}}$.