Leonardo da Vinci suggested a flying machine designed to act like a screw and raise the pilot into the air. The pilot turns the ‘screw’. The combined mass of the machine and the pilot is $120\,\text{kg}$. Which useful output power is needed for the pilot to travel straight upwards at a steady speed of $2.5\,\text{m s}^{-1}$?
- A$48\,\text{W}$
- B$300\,\text{W}$
- C$470\,\text{W}$
- D$2900\,\text{W}$