Download Slide 1

PMO Motion
Benchmark 2
Explain energy conversions
in moving objects and
machines.
Types of Energy
There are three types of energy:
Kinetic
Potential
Radiant
Kinetic Energy is the energy of MOTION.
Potential Energy is STORED energy.
Radiant Energy is energy associated with waves from the
electromagnetic spectrum (heat, radiation, light, etc.).
Kinetic Energy
Kinetic Energy is the energy of motion. Any object in motion
has Kinetic Energy.
The amount of Kinetic Energy depends on two factors:
1. The mass of the object.
2. The speed of the object.
Which has more Kinetic Energy?
A bowling ball rolling down the hallway at 1 m/s or a bowling ball
rolling down the hallway at 5 m/s?
A bowling ball rolling down the hallway at 1 m/s or a golf ball rolling
down the hallway at 1 m/s?
Potential Energy
Potential Energy is stored energy. Energy can be stored in
various forms.
1. Energy can be stored by raising an object above the ground
(gravitational potential energy).
2. Energy can be stored by compressing or stretching a spring
(elastic potential energy).
3. Energy can be stored in the chemical bonds of a compound
(chemical potential energy).
4. Energy can be stored in the form of electricity (electrical
potential energy).
Energy can be released from each of these forms into
Kinetic Energy!
Radiant Energy
Radiant Energy is energy associated with waves from the
electromagnetic spectrum (heat, radiation, light, etc.). There are
various forms.
1. Heat from any source (the sun, fire, etc.) is infrared waves.
2. Visible Light Energy can be stored by compressing or
stretching a spring (elastic potential energy).
3. Gamma Rays and X-Rays are high energy electromagnetic
waves.
Energy Transformations
Energy is never created or destroyed; it is only converted from
one form to another.
This is called the LAW OF CONCERVATION OF ENERGY.
Gravitational
Potential
Ball rolling
down a hill
Elastic
Potential
Launching a
water balloon
Electrical
Potential
A light bulb
lighting
Radiant
Kinetic
Kinetic
Chemical
Potential
Burning
wood
Radiant
Real-world contexts
Simple and complex machines
roller coasters
swings
pendulums
elevators
automobiles
fans
motors
Pendulums
The TOTAL ENERGY
IS CONSTANT
Energy transformations are
easily seen in pendulums.
A pendulum is released from a
height H above its lowest height.
Where is it moving the fastest?
Is it ever stopped?
How high will it rise on the
opposite side?
Describe the energy
conversions as it swings.
H
Roller Coasters
Energy transformations are
easily seen in roller coasters.
A roller coaster car travels from
the high points to the low points.
Where is it moving the fastest?
Where is it moving the slowest
Describe the energy
conversions as it rolls.
The TOTAL ENERGY
IS CONSTANT
Friction
Friction occurs when two objects rub against one another.
Friction generates heat (radiant energy) and gives it off to the
surroundings.
Therefore the height of a real pendulum will decrease over time,
the gravitational potential and kinetic energies are being converted
to radiant energy.
Web Exploration
http://physics.weber.edu/amiri/director/DCRfiles/Energy/bungee4s.dcr
http://www.phy.ntnu.edu.tw/java/Pendulum/Pendulum.html
http://www.walter-fendt.de/ph11e/springpendulum.htm
http://www.funderstanding.com/k12/coaster/