Download Energy

What is energy?
Energy is the ability
to do work
 Any object with energy has the
ability to create force and make
things move.
Ex – Mechanical, Chemical,
Nuclear, Radiant.
 • A moving ball has energy because it can create
forces on whatever tries to stop it or slow it down.
 • A sled at the top of a hill has energy because it can
go down the hill and produce forces as it goes.
 • The moving wind has energy because it can create
forces on any object in its path.
 • Electricity has energy because it can turn a motor
to make forces.
 • Gasoline has energy because it can be burned in
an engine to make force to move a car.
 • You have energy because you can create forces.
What is energy?
Energy is measured in
Joules (J)
A joule is the energy it
takes to move 1 Newton
a distance of 1 meter.
1 Joule = 1 newton-meter
Potential Energy
 Potential Energy is energy that an object
has due to the position of the object, or due
to its unique properties .
 Ex. Stretched Spring, Ball lifted above the
ground, Gasoline, or a piece of wood.
Potential Energy
 Gravitational potential energy is
energy from position.
 Depends on mass, gravity and
height.
Ep = mgh
 Potential energy = mass (kg)
* gravity (m/s/s) * height (m)
Kinetic Energy
 Moving mass can exert forces.
 Energy of motion is called Kinetic
Energy!
Ek = ½
2
mv
•Kinetic Energy
increases with
speed
•Kinetic energy
increases with
mass
7.2 Energy Transformations
 Energy can change from one
form to another.
 When energy is lost as one
form, it is gained as another.
7.2 Energy flow
 Systems tend
to move from
higher to
lower energy.
7.2 Sources of energy

The chemical potential energy stored in
the food you eat is converted into simple
sugars that are burned as your muscles
work against gravity as you climb the hill.
7.2 Units of energy
 Some units of energy that are
more appropriate for everyday
use are the kilowatt hour (kWh),
food Calorie, and British thermal
unit.
Law of Conservation of Energy
 Energy can never be created
or destroyed!
 Energy only gets converted
to one form or another.
 This is called the
Law of Conservation of
Energy!
7.3 Conservation of Energy
 Many people are concerned about
“running out” of energy.
 What they worry about is running
out of certain forms of energy that
are easy to use, such as fossil fuels
like oil and gas.
7.3 Conservation of Energy


It took millions of years to
accumulate these fuels
because they are derived from
decaying, ancient plants that
obtained their energy from the
Sun when they were alive.
Because it took a long time for
these plants to grow, decay,
and become oil and gas, fossil
fuels are a limited resource.
7.3 Conservation of Energy
 Regular
(incandescent) light
bulbs convert only
10% of electrical
energy to light.
 That means 90% of
the energy is
released as wasted
heat.
7.3 Conservation of Energy
 Other forms of
energy, such as
thermal energy,
flowing water,
wind, and solar
energy are not as
limited.
Mechanical Energy
 Is the energy possessed by an object due
to its position or its motion
 Mechanical energy is either Potential or
kinetic energy.
Electromagnetic Energy
 Is a form of energy that is reflected or
emitted from objects in the form of
electrical and magnetic waves that can
travel through space.
 There are many forms of electromagnetic
energy including gamma rays, x rays,
ultraviolet radiation, visible light, infrared
radiation, microwaves and radio waves.
Radiant Energy
 Is the Electromagnetic Energy from the
sun.
 Harnessed as solar power.
Electrical Energy
 Is energy made available by the flow of
electric charge.
 Electrical energy is actually derived from
other sources of energy.
 Usually from the production of heat energy, through
burning something, which is then used to boil water
and produce steam which is used to turn a
generator, which produces electrical energy.
Chemical Energy
 Is the type of energy stored in molecules.
 Chemical Reactions can either use or
release chemical energy.
Nuclear Energy
 Coming from the splitting
of an atom, or fusing two
atoms together, when this
happens a huge amount
of energy is released.
 This is used primarily to
generate electricity or as a
weapon of mass
destruction.
I'm not sure what weapons will be used in
World War III,but World War IV will be fought
with sticks and stones."~Albert Einstein
Heat Energy, Thermal
Energy
 Any heat that radiates from a heat source.
Natural Potential Energy
 Don’t forget about
 Solar Power
 Geothermal Energy
 Wind Energy
 Tidal Energy
 Water Energy
 Biomass Energy