12.5 Exercise 12

Gasoline is piped underground from refineries to major users. The flow rate is $3 . \text{00} \times \text{10}^{–2} \text{m}^{3} /\text{s}$ (about 500 gal/min), the viscosity of gasoline is $1.00 \times \text{10}^{–3} \left(\right. \text{N}/\text{m}^{2} \left.\right) \cdot \text{s}$, and its density is $\text{680} \text{kg}/\text{m}^{3}$. (a) What minimum diameter must the pipe have if the Reynolds number is to be less than 2000? (b) What pressure difference must be maintained along each kilometer of the pipe to maintain this flow rate?