A maintenance platform is raised vertically at a steady speed inside a tower. The platform rubs against guide rails as it moves.
The table shows measured energy changes as the platform moves through two sections of the tower.
| Section | Vertical distance moved (m) | Increase in gravitational potential energy store (J) | Energy transferred to thermal stores (J) |
|---|---|---|---|
| A | 4.0 | 7200 | 800 |
| B | 6.0 | 10 800 | 1800 |
Calculate the force exerted by the cable while the platform moves through section A.
An engineer claims that the cable exerts the same force in section B. Predict the energy transferred to thermal stores in section B if the claim is correct. Evaluate the claim using the measured value.