Air enters a pipe $(f=0.02)$ of diameter $0.05 \mathrm{~m}$ with stagnation pressure and temperature equal to $1 \mathrm{MPa}$ and $300 \mathrm{~K}$, respectively. The pipe exhausts into the ambient at $100 \mathrm{kPa}$. Determine the length of the pipe required to achieve a mass flow rate of $2 \mathrm{~kg} / \mathrm{s}$. Assume the flow to be subsonic at the entrance of the pipe.