A rider of mass 40 kg starts from rest and descends a water slide. The table shows the vertical height lost and the energy transferred to thermal stores by the time the rider reaches each checkpoint. Use g=10 N/kgg=10\ \mathrm{N/kg}g=10 N/kg.
| Checkpoint | Vertical height lost (m) | Energy transferred to thermal stores (J) |
|---|---|---|
| B | 6.0 | 600 |
| C | 18 | 4000 |
Calculate the speed of the rider at checkpoint B.
A student claims that the rider's speed at checkpoint C is three times the speed at checkpoint B because the vertical height lost is three times greater. Compare the speeds at B and C and assess this claim.