Question

. Indiana Jones needs to ascend a 10-m-high building. There is a large hose filled with pressurized water hanging down from the building top. He builds a square platform and mounts four 4-cm-diameter nozzles pointing down at each corner. By connecting hose branches, a water jet with a velocity, u, can be produced from each nozzle. Jones, the platform, and the nozzles have a combined mass of 150 kg. Determine the minimum water jet velocity, u (m/s), needed to raise the system.

Answer 1

u = 14 m / s

Step-by-step explanation:

For this exercise let's use conservation of energy

starting point. On the floor just when u speeding out

Em₀ = K = ½ m v²

final point. When on top of the building, no speed

Em_f = U = m g h

energy is conserved

Em₀ = Em_f

½ m v² = m g h

v = u

u =

u=

u = 14 m / s