Answer:
No, the claim is not reasonable for 20 W electric power consumption.
It is reasonable for 40 W electric power consumption.
Explanation:
Power = (1/2)*mass flow rate*(square of velocity)
mass flow rate = 1 kg/s
velocity = 8 m/s
square of velocity = 64 m^2 / s^2
Power = (1/2)*(1)*(64)
Power = 32 W
For a fan that consumes 20 W power it is not possible to deliver more power than 20 W but this one is delivering 32 W hence it is a false claim.
For a fan that consumes 40 W it is indeed possible to deliver 32 W considering the efficiency. Hence this claim is reasonable.
