Air enters a 11-m-long section of a rectangular duct of cross section 15 cm × 20 cm made of commercial steel at 1 atm and 35°c at an average velocity of 5 m/s. disregarding the entrance effects, determine the fan power needed to overcome the pressure losses in this section of the duct. the properties of air at 1 atm and 35°c are rho = 1.145 kg/m3, μ = 1.895 × 10–5 kg/m·s, and ν = 1.655 × 10–5 m2/s. the roughness of commercial steel surfaces is ε = 0.45 m. the fan power needed to overcome the pressure losses is

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.

reserve is the answer