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Welcome to the
world of energy!
DO YOU HAVE ANY
TODAY?????
Topics to Be
Covered
What is energy?
What kinds of energy
are there?
Law of conservation of
energy
Power
Machines
Sources of energy
What is energy?
Energy is the
ability to do
work.
Work = Force
times distance
What is energy?
If something is moving it
has energy
We call the energy of
motion kinetic energy
Objects can have energy even
if they are not moving. An
example is potential energy
due to gravity.
potential energy
There are several types
of potential energy
 gravitational
Elastic
chemical
potential energy
AN OBJECT THAT IS
MOVING HAS
KINETIC ENERGY
BUT CAN ALSO HAVE
potential energy
What kinds of energy are there?
Mechanical (potential, kinetic)
electrical
thermal
light
sound
nuclear
chemical
Law of conservation
of energy
Energy cannot be created or
destroyed. It changes from one form
to another but the total energy never
changes..
 An example of this is when you rub
your hands together (mechanical
energy) and you feel heat (thermal
energy). It actually starts with
chemical energy from your body.

Power
The rate at which energy
is changed (or work is
done) is called power.
 If something is very
powerful, it can do work
quickly. Example: race
car
Powerful formula
Power = work
time
Power
Machines
Devices for
multiplying forces
or changing the
direction of forces.
Effects of machines
Machines can
make the work
easier to do.

Sources of energy
Sun (solar, wind, water)
Fossil fuels (from sun)
Nuclear
Geothermal
Work-Energy Theorem
Work-Energy Theorem
Change in Potential energy
= change in kinetic energy
= work done
Summary
Energy is the ability to
do work
The two forms of
mechanical energy are
potential and kinetic
energy
Summary

Work is
force X distance
Machines make work
easier by reducing force.
Power is work/time
Cool energy
transformations!