1. Work, Energy, and Power Energy, Work, and Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Work, Energy, and Power

2. Energy, Work, and Power
Work = W
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
The product of the force F applied to an object over a distance d in which the object travels as a result of the force
(Force and distance must be parallel to each other)
Joule (J) is the base unit of work

3. Work Example
Energy, Work, and Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
A student lifts a 50 pound (lb) ball 4 feet (ft) in 5 seconds (s).
How many joules of work did the student complete?
Convert English units to SI units
Solve for Work

4. Energy Ability to do work
Energy, Work, and Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Ability to do work
Light, heat, mechanical, chemical, and electrical forms of energy can all be used to exert a force for a distance.
Roller coaster
NASA solar sail
Fuel cell

5. Energy, Work, and Power
Forms of Energy
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Potential Energy (Stored energy, usually referring to gravitational energy)
The capacity to do work by virtue of position or configuration

6. Forms of Energy Kinetic Energy (Energy of motion)
Energy, Work, and Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Kinetic Energy (Energy of motion)
Energy which a body possesses because of its motion, which occurs anywhere from an atomic level to that of a whole organism
Examples of Kinetic Energy: This is not an all-inclusive list.
Electrical – The movement of electrons
Thermal or Heat – The movement of molecules
Motion – The movement of objects
Engineers generally refer to thermal/heat energy as “internal energy” and use “kinetic energy” strictly in reference to motion.

7. Energy Transformation
Energy, Work, and Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
ChemicalKinetic
Radiant Chemical
Energy transformation involves the conversion of one form of energy into another form.
Examples of energy transformation include:
Chemical to Kinetic – Food is consumed and converted into motion for playing sports or taking a test.
Radiant to Chemical – Sunlight is consumed by plants and converted into energy for growth.
Electrical to Thermal – Energy transferred to an oven is converted to thermal energy for heating our food.
Electrical  Thermal

8. Renewable Energy Sources
Energy, Work, and Power
Renewable Energy Sources
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Biomass
Hydropower
Geothermal
Wind
Solar
Now you know the basic forms of energy. The next question is “What are the energy sources?”
There are renewable and nonrenewable sources of energy. A renewable energy source is a form of energy that is constantly and rapidly replenished by natural processes.
Examples of renewable energy sources include:
Biomass – The use of a living or once living organism as fuel
Hydropower – The energy produced from the movement of water
Geothermal – The use of heat from within the Earth or from the atmosphere near oceans to warm houses or other buildings
Wind – The use of wind to generate electricity
Solar – The use of the sun as a source of heat; for instance, to heat a room within a house, etc.

9. Nonrenewable Energy Sources
Energy, Work, and Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Coal
Natural Gas
Petroleum
Uranium
A nonrenewable energy source is one that is obtained from the Earth as a liquid, gas, or solid and cannot be replenished in a rapid manner.
Examples of nonrenewable energy sources include:
Petroleum
Natural gas
Coal
Uranium
Propane

10. Conservation of Energy
Energy, Work, and Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Energy cannot be created or destroyed, but it can change from one form to another.
Energy Conversion
Changing one form of energy to another
Energy Efficiency: The ratio of the useful energy delivered by a dynamic system to the energy supplied to it
Entropy: The increasing disorder when energy is transformed to heat during conversion

11. Which output is desired, mechanical or heat?
Energy, Work, and Power
Energy Conversion
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Examples
Fossil fuels Chemical → Heat → Mechanical → Electrical
Solar cells Sunlight → Electrical
Wind turbines Kinetic → Mechanical → Electrical
Hydroelectric Gravitational potential → Mechanical → Electrical
Nuclear Nuclear → Heat → Mechanical → Electrical
Vehicle System Conversion
What is done with electrical energy?
Chemical
Mechanical
Heat
Which output is desired, mechanical or heat?

12. What Are Current Energy Concerns?
Energy, Work, and Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
What Are Current Energy Concerns?
Consumption
Pollution
Depletion
Dependency
Cost
What roles do engineers have in energy?

13. Power Watt is the base unit of Power
Energy, Work, and Power
Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Rate at which work is performed or energy is expended
Watt is the base unit of Power
One watt is equal to 1 joule of work per second

14. Types of Power Electrical Power Uses electrical energy to do work
Energy, Work, and Power
Types of Power
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
Electrical Power
Uses electrical energy to do work
Mechanical Power
Uses mechanical energy to do work (linear, rotary)
Fluid Power
Uses energy transferred by liquids (hydraulic) and gases (pneumatic)

15. Energy, Work, and Power
Power Example
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
A student lifts a 50.0 pound (lbf) ball 4.00 feet (ft) in 5.00 seconds (s).
How many watts of power are used to lift the ball?
Work = J

16. Energy, Work, and Power
Resources
Principles of EngineeringTM
Unit 1 – Lesson 1.2 – Work, Energy, and Power
McGraw-Hill dictionary of engineering. (2nd ed.). New York, NY: McGraw-Hill.
Microsoft, Inc. (2008). Clip art. Retrieved January 10, 2008, from
National Aeronautics and Space Administration (NASA). (1997). Daedalus. Retrieved April 2, 2008, from /Photo/Daedalus/
U.S. Department of Energy. (2008). Scientific forms of energy. Retrieved March 23, 2008, from