Force, Pressure, Head, and Velocity Calculations - Basic Mathematics for Water and Wastewater Operators - page 184

Solution :

1. Convert flow to cfs.

1400 gpm ÷ 449 gpm/cfs = 3.12 cfs

2. Change inches to feet.

8 in. ÷ 12 in./ft = 0.666 ft

3. Find the area of the pipe in square feet.

Area = π × r 2 = 3.14 × (0.333 ft) 2 = 0.349 ft 2

4. Find the velocity in fps.

Velocity = 3.12 cfs ÷ 0.349 ft 2 = 9 fps

■ Example 12.22
Problem : A rocket traveled 4200 ft in 6 seconds. What was the velocity of the
rocket in feet per second?

Solution:

Distance
Time

4200 ft
6sec

Velocity = = = 700 fps

■ Example 12.23
Problem: A bobber is placed in a stream and travels 520 ft in 2.5 minutes. What is
the velocity of the water flowing in the stream in feet per minute?

Solution:

Distance
Time

520 ft
2.5 min

Velocity = = = 208 ft/ min

■ Example 12.24
Problem : A cork is placed in a channel and travels 390 ft in 2 minutes. What is the
velocity of the water in the channel in feet per minute?

Solution:

Distance
Time

390 ft
2 min

Velocity = = = 195 ft/mi n