A motorised stage platform starts from rest and travels along a straight, level floor. The driving force from the motor and the frictional force opposing the motion are constant within each section of the journey.
| Section | distance travelled / m\mathrm{m}m | driving force / N\mathrm{N}N | frictional force / N\mathrm{N}N |
|---|---|---|---|
| 1 | 1.5 | 140 | 40 |
| 2 | 2.0 | 110 | 60 |
Immediately after section 2, the motor is switched off and the brakes are applied. The total resistive force on the platform is then constant and brings the platform to rest over a distance of 0.80 m.
Calculate the total resistive force on the platform while it is braking.