# Principles of Technology

## Fluid Resistance (4:2)

### Review Worksheet

If you understand and can do these problems you should do well on the quiz.

1. List the appropriate formulas and units in the boxes below.

#### Units (SI / English)

2. Water flows through a 10 foot pipe at a flow rate of 0.75 m3/sec. It undergoes a pressure drop of 150 N/m2. Find the resistance of the pipe.

3. The resistance in a fuel-transfer pipeline is 3 (lb/in2) / (gal/min). The line is 6.75 inches in diameter. Fuel moves through the line at a volume flow rate of 650 gal/min. Find the pressure difference along the length of the pipeline.

4. A fluid flows through a certain length of pipe at 0.075 m3/sec and undergoes a pressure drop of 2000 N/m2. Calculate the fluid resistance of the pipe.

5. In order to run water to all the trees in an orchard, would it be better to run just one pipe with a sprinkler at each tree, or hook the rows all up in a parallel system? WHY?

6. A hose has a resistance Rf equal to 0.5 (lb/in2) / (gal/min). What pressure drop across the hose is needed to produce a flow rate of 20 gal/min?

7. An air hose is 30 feet long, and has a flow rate of 5 gal/min. There's a pressure drop of 12 lb/in2.

7a. What is the flow rate of this hose?

7b. What will be the flow rate if an identical hose is connected, in series, to the first?

8. Water flowing through a pipe at 18 ft3/min has a pressure difference of 200 lb/in2 over a distance of 2.2 miles. Find the resistance (Rf) that causes the pressure difference.

9. An air compressor delivers air to a receiver tank at 135 lbs/in2. A 120 foot air hose with a pressure drop of 2.3 lbs/in2 for each 15 foot of length is connected to the tank. The hose operates an air tool.

9a. Find the pressure at the air tool in lbs/in2 and lbs/ft2.

9b. Find the resistance in the air hose if the tool requires 20 ft3/min of air to operate.