Energy, Work, and Power
Principles of Engineering
Unit 1 – Lesson 1.2 – Energy Sources
Work (W)
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)
Work, Energy, and Power
Work Example
A student lifts a 50 pound (lb) ball 4
feet (ft) in 5 seconds (s).
How many joules of work has the
student completed?
Joule (j) is the base unit of work
Energy
Ability to do work
(light, heat, mechanical, chemical, electrical)
Convert English units to SI units
Solve for Work
Roller coaster
Forms of Energy
Potential Energy (Stored energy or gravitational energy)
The capacity to do work by virtue of position or
configuration
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NASA solar sail
Fuel cell
Forms of Energy
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
Energy, Work, and Power
Principles of Engineering
Unit 1 – Lesson 1.2 – Energy Sources
Energy Transformation
Renewable Energy Sources
Biomass
Hydropower
Hydropowe
Geothermal
Chemical
Radiant
Solar
Wind
Electrical
Nonrenewable Energy Sources
Natural Gas
Coal
Conservation of Energy
Energy cannot be created or destroyed, but it
can change from one form to another.
Energy Conversion
Changing one form of energy to another
Uranium
Petroleum
Energy Efficiency: The ratio of the useful energy
delivered by a dynamic system to the energy
supplied to it
Entropy: The loss of energy during conversion
Energy Conversion
Examples
Fossil fuels
Solar cells
Wind turbines
Hydroelectric
Nuclear
What Are Current Energy Concerns?
Chemical → Mechanical → Electrical
Sunlight → Electrical
Kinetic → Mechanical → Electrical
Gravitational potential → Mechanical → Electrical
Nuclear → Heat → Mechanical → Electrical
Consumption
Pollution
Depletion
Dependency
Cost
Vehicle System Conversion
Chemical
Mechanical
Heat
Which output is desired, mechanical or heat?
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What roles do engineers have in energy?
Energy, Work, and Power
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
Power Example
A student lifts a 50 pound (lb) ball 4 feet (ft) in 5
seconds (s).
How many watts of power are used to lift the
ball?
Power = Work / Time
Work = 271.45J
Principles of Engineering
Unit 1 – Lesson 1.2 – Energy Sources
Types of Power
Electrical Power
Uses electrical energy to do work
Mechanical Power
Uses mechanical energy to do work
(linear, rotary)
Fluid Power
Uses energy created by liquids (hydraulic)
and gases (pneumatic)
Resources
McGraw-Hill dictionary of engineering. (2nd ed.). New York,
NY: McGraw-Hill.
Microsoft, Inc. (2008). Clip Art. Retrieved January 10, 2008,
from http://office.microsoft.com/en-us/clipart/default.aspx
National Aeronautics and Space Administration (NASA).
(1997). Daedalus. Retrieved April 2, 2008, from
http://www.dfrc.nasa.gov/Gallery /Photo/Daedalus/
U.S. Department of Energy. (2008). Scientific forms of
energy. Retrieved March 23, 2008, from
http://www.eia.doe.gov/kids/energyfacts/science/formsof
energy.html
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Copyright 2010