Download What are Kinetic and Potential Energy?

Bellringer
1. What biome has few trees and lots of grasses
with a long dry season and a short wet
season?
2. What do we call the variable that we
measure in an experiment?
3. What phase of the moon does a lunar eclipse
occur?
4. What type of tide occurs during 1st and 3rd
quarter moons?
Bellringer
1. What biome has trees with leaves that have a
waxy coating and cool temperatures?
2. What organisms get their energy from the
sun?
3. What phase of the moon comes after waxing
crescent?
4. What eclipse occurs during a new moon?
5. What is the original source of wind?
What are Kinetic
and
Potential Energy?
What is Energy?
• Energy is the ability to do work.
• Work is done when a force causes an object to
move in the direction of the force.
• Everything that happens in the world uses
energy!
• Most of the time we can’t see energy, but it is
everywhere around us!
Energy…
• Law of Conservation of Energy-energy can
NEVER be created or destroyed! It can only be
STORED or TRANSFERED.-
How is all energy divided?
All Energy
Potential
Energy
Kinetic
Energy
Kinetic Energy
• In tennis, energy is transferred from the racket
to the ball. As it flies over the net, the ball has
kinetic energy.
• Kinetic energy is the energy of motion.
• All moving objects have kinetic energy.
• Like all forms of energy, kinetic energy can be
used to do work. For example, kinetic energy
allows a hammer to do work on a nail.
Examples of Kinetic Energy:
Kinetic Energy
Two things can affect the amount of kinetic energy
of something.
1. Its mass…. Simply put, the bigger something is,
the greater its energy.
2. Its velocity(speed)…. Again, pretty simple. The
faster it moves, the more energy it has.
KE = M x V
(This might remind you of the formula for force….
How do force and energy relate to each other?)
• The faster the object
moves, the more
kinetic energy is
produced.
• The greater the mass and speed of an object,
the more kinetic energy there will be.
When these objects move at the same
speed, which will have more kinetic
energy?
ANSWER
The semi- truck has more mass;
therefore, more kinetic energy!
Potential Energy
• Is the energy an object has because of its
position.
• Example:
– The bow has energy because work has been
done to change its shape.
Potential Energy is…
• The energy stored in an object.
• "Potential" simply means the energy has the
ability to do something useful later on.
Example of Potential Energy
Potential Energy
The ball at the top of the hill
has a great deal of potential
energy.
Kinetic vs. Potential Energy
At the point of maximum potential energy, the car has
minimum kinetic energy.
Kinetic-Potential Energy Conversions
• As a basketball player
throws the ball into the
air, various energy
conversions take place.
Ball slows down
Ball speeds up
Elastic Potential Energy
• Energy can be stored in bowstrings, springs,
and rubber bands.
• You change the shape of these objects by
stretching them.
Gravitational Potential Energy
• When an object is lifted off the Earth’s
surface.
• You use a force that is against the force of
gravity.
• Books on a shelf have gravitational potential
energy.
Chemical Potential Energy
• Potential energy stored in chemical bonds.
• Before you eat that sugary drink or food, it
has the potential to give you energy.
• Food and drinks have chemical potential
energy due to their chemical composition.
Chemical Potential Energy
• Batteries, gasoline, matches, and fireworks
also have chemical potential energy.
Practicing with whiteboards
Potential or Kinetic?
An apple on a tree.
Potential or Kinetic?
A rolling ball.
Potential or Kinetic?
A stretched rubber band.
Gravitational, Elastic, or Chemical?
Our food and drink.
Gravitational, Elastic, or Chemical?
A book on a shelf.
Gravitational, Elastic, or Chemical?
A stretched rubber band.
Which object has more potential energy?
B
A
Changing an objects’ height can change its
potential energy.
• If I want to drop an apple from the top of one of these
three things, where will be the most potential energy?
A
B
C
Which one has more Kinetic energy?
If Ms. Russell rolled a bowling
ball and a soccer ball down
the aisle at the same speed,
which one would have more
kinetic energy?
Which one has more Kinetic Energy?
A red tennis ball rolling slow
or a blue tennis ball rolling
fast?