# Principles of Technology

## Fluid Work (2:2)

### Vocabulary (pages 35-41)

What is the general (unifying) equation for work

Pressure difference

What does the symbol "delta" mean

Open system (with an example not in book)

Closed system (with an example not in book)

After reading "Basic Hydraulic Power System" on page 37 and looking at figures 2-11a and 2-11b, explain in your own words how a closed hydraulic system works.

Formula for work in an open system

Formula for work in a closed system

Re-arrange the equations to solve for all variables

### Closed Fluid System

Why do you think heavy-duty hydraulic cylinders use oil as the fluid instead of air?

On the back Re-work example 2-F (page 39) using the following values: 637 cubic feet of water and 225 feet above lake level. Show all formulas and work for every step.

On the back Re-work example 2-G (page 40) using the following values: 37 centimeters of horizontal displacement, 50,000 N/m^2 of pressure, and a surface area of 25 cm^2. Show all formulas and work for every step.