A motorised loading platform of mass 1500 kg moves in a straight line. Its driving force is 3600 N forwards. The driving force and resistive force are constant, and the platform accelerates uniformly. Its velocity changes as shown.
| Time interval | Initial velocity | Final velocity |
|---|---|---|
| 3.0 s | 2.0 m s−12.0\ \mathrm{m\,s^{-1}}2.0 ms−1 | 5.0 m s−15.0\ \mathrm{m\,s^{-1}}5.0 ms−1 |
Calculate the resistive force acting on the platform.