A spacecraft is tested under two conditions. The resultant force on it acts forwards in each condition.
| Quantity | Condition 1 | Condition 2 |
|---|---|---|
| Resultant force | 1200 N | 1800 N |
| Mass of spacecraft | 6000 kg | 5000 kg |
The spacecraft's acceleration is greater in condition 2.
Explain why the acceleration is greater in condition 2.