An elevator is created by using a hose hanging from the top of a 10 m building. The hose is diverted into 4 jets at the corners of a platform pointing downwards. The nozzles at the exits are 5 cm in diameter and have a maximum velocity of 15 m/s. The platform and person ontop have a combined mass of 150 kg.
Determine:
a) the minimum water jet velocity needed to raise the system,
b) how long it will take for the system to rise 10 m when the water jet velocity is 15 m/s and the velocity of the system at that moment and
c) how much higher the momentum will raise the person if the water is shut off at the moment the platform reaches 10 m above the ground. How much time would the person have to jump off the platform onto the roof?