types of potential energy. avalanche questions where did the energy of the avalanche come from?...

Types of Potential Energy

Avalanche Questions

• Where did the energy of the avalanche come from?

• Where did it go?

Energy Conversion

•Energy can be converted from one form to another

•Energy conversion is the process of this change

Conservation of Energy

•Law of Conservation of Energy•Energy cannot be created nor

destroyed

•Energy changes from one form to another, but the total amount of energy remains unchanged

Energy Transformation

•Each time energy is transformed, all of the energy can be accounted for—none of the energy is lost!

Two General Types of Energy

Kinetic Energy• Energy of

Motion

Potential Energy

• Energy that is stored as a result of position or shape

• Energy with the potential to do work

• Examples: • Lifting a book in the

air• Plucking a string

Mechanical Energy

• The sum of kinetic and potential energy of a system

• EXAMPLE – Pendulum

Types of Energy

Review Game

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Drop Height v. Height of Can

Drop Height (cm)

Height of Can (cm)

Mass v. Height of CanMass

(g)Height of Can (cm)

MYSTERY MASS

Analysis Questions

• What factors affect the amount of gravitational potential energy an object is storing?

• What is the relationship between GPE and height? Between GPE and mass?

• Which can crusher situation would have the most GPE? The least GPE?

Gravitational PE• Energy is stored as the result of the gravitational attraction of the

Earth for the object.

• Depends on TWO factors

1. Mass of an Object

2. Height above the surface of Earth

• Relationship Between GPE and Mass• As mass of an object increases, the GPE of the object increases

• Relationship Between GPE and Height• As the height of an object above ground increases, the GPE of the

object increases

GPE

Maximum GPE

IncreasingGPE

DecreasingGPE

Gravitational PE Practice Problems

#1• Who has

greater GPE: a diver standing on a 10m diving board OR a diver standing on a 15m diving board?

#2• If a diver is

standing on the ground. What is her gravitational PE? Why?

Meteor Crater in Arizona

Manicouagan inQuebec, Canada

Chicxulub onthe Yucatan coast in

Mexico

Quick Video!

• https://www.youtube.com/watch?v=YzFDCsCscyo

• Think about the types of PE acting on the bouncy balls in this video.• Where does the energy come

from? Where does it go?• Why do the bouncy balls

eventually come to a stop?

PLICKER!Green, Yellow, Red

Elastic Potential Energy

• Energy stored in elastic materials as the result of their stretching or compressing

• A change in the amount of compression or stretch of an elastic object is evidence that the elastic potential energy has changed.

• Example: When you stretch a rubber band, the elastic potential energy of the rubber band increases. This stored energy can cause the rubber band to fly across the room when you let it go.

Elastic PE

• Butterfly Demonstration

• Marshmallow Launcher Demonstration

Windup Toy

DemonstrationWhen you wind up the windup toy, potential energy is stored in its spring. As you wind the spring tighter and tighter, the spring holds more potential energy. The kind of potential energy in the spring of a windup toy is elastic potential energy. Elastic potential energy is stored when something “stretchy” or “springy” is stretched or compressed. When you wind up the windup toy, you compress its spring. When you let go, the spring unwinds, and the toy moves.

Energy Transformations

PLICKER!

Chemical PE• The energy stored in bonds between the atoms that

make up matter

• Chemical potential energy can be released during chemical reactions when these bonds are broken

• Examples:1. You get energy by eating because food contains chemical potential energy. Your body breaks down bonds between atoms when you digest food. The process of breaking down food converts the CPE stored in food to other types of energy your body needs in order to function.2. Fossil fuels have CPE. CPE is released when fossil fuels such as gasoline are burned.

Magnetic PE

• Magnetic potential energy is associated with the position of magnetic objects relative to each other

• Magnetic force weakens rapidly with increasing distance• This means that as two magnets move farther away

from one another, the magnetic force acting on them decreases

• OR as a magnetic material is moved farther away from a magnet, the magnetic force acting on the magnetic material decreases

Electrical PE

• Charged particles are particles that have either a positive (+) or negative (-) electrical charge.

• Depends on TWO factors1.Amount of electrical charge an object has2.Distance between charged particles

• A change in the position of charged particles relative to each other is evidence of a change in electrical potential energy.