Final answer:
The magnitude of the momentum of the spacecraft, once it has left Mars and is coasting far away, is calculated using the formula p = mv, resulting in a momentum of 9 × 10^6 kg·m/s.
Step-by-step explanation:
The magnitude of the momentum of a spacecraft when it is far away from Mars can be determined using the formula for momentum, which is p = mv, where p is momentum, m is mass, and v is velocity. In this case, the mass of the spacecraft (m) is 5000 kg and the velocity (v) when it is coasting far away is 1800 m/s.
To find the magnitude of the momentum, simply multiply the mass of the spacecraft by the velocity:
p = (5000 kg) × (1800 m/s) = 9 × 10^6 kg·m/s
Thus, the magnitude of the momentum of the spacecraft when it is far away from Mars is 9 × 10^6 kg·m/s.