Download Kinetic energy - mrs

Unit 4
Mechanical Systems
Topic 3
Energy, Friction, Efficiency
Remember to name and date your
notes!
Kinetic energy – energy present
in moving objects.
Potential energy – stored energy
• Potential Energy is energy that
is stored in something and is
“potentially available.”
• There are many forms of
potential energy.
Some forms of energy:
• Thermal energy (heat) is the total
energy of all the moving particles
in a material or object.
• Chemical energy is the energy
stored in foods and fuels.
• Mechanical energy is the energy
associated with machines
Some Other Forms of
Energy
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Solar Energy
Sound Energy
Tidal Energy
Gravitational Energy
Light Energy
Wind Energy
An energy converter is any
device that can convert energy
from one form to another.
An energy transmitter, energy is
transmitted from one place to
another, but no energy is
converted.
• The school bell converts
chemical energy to mechanical
energy to sound energy.
The mechanical mouse converts
chemical energy (from our
bodies) to mechanical energy.
What conversion happens in a
solar heater?
A solar heater converts light
energy into heat energy.
(Or light into electrical)
What energy conversion takes
place in a toy rocket?
The rocket changes chemical
energy to mechanical energy,
heat energy, light energy and
sound energy.
The efficiency of a machine
tells you how much of the
energy you gave to the
machine was transferred to
the load by the machine.
Efficiency = output energy
input energy
• Every time a machine does
work, some energy is lost
due to friction. (Ie. Blades on
scissors rubbing together.)
• Make machines more
efficient by reducing friction
– adding lubricant such as oil
or grease.