Energy
Potential
Gravitational potential energy (GPE)
The potential of an object to do work because of its relative
position
o A ball held in the air
Elastic potential energy
The energy stored in an object when it is stretched or deformed
o A stretched rubber band
Chemical potential energy
The energy stored in the bonds between atoms, released as heat,
sound or light during chemical reactions such as burning
o Batteries
Nuclear potential energy
The energy stored in the nucleus of atoms, may be released
quickly as a nuclear explosion or controlled slowly in a nuclear
reaction
o Nuclear fission
Kinetic
Active energy
The energy that an object has because of its movement
o A thrown ball
Heat energy
The motions of atoms or molecules in a substance or object
o The sun
Sound energy
The vibration of particles, can be detected by the ear.
o A loud clap
Light energy
A form of electromagnetic radiation emitted by hot objects. It is
usually visible light
o A torch beam
Electrical energy
The energy generated by moving electrons
o Lightning
Mechanical energy
The energy of an object in motion and the energy that is stored
in objects by their position, combined GPE and active energy
o Car rolling down a hill (GPE and active energy)
1
,Energy Transformations
The conversion of energy from one form to another.
Battery: Chemical to electrical.
A swing: GPE to kinetic to GPE.
The sun: Nuclear to light and heat.
Energy Transfers
The movement of the same energy form from one object to
another.
A bowling ball hits another bowling ball.
Electricity going along a wire.
Heat going from a hot pan to a hand.
Energy Wastage and Efficiency
Wasted energy is energy that is not transferred or transformed
usefully. Common sources of wasted energy include:
Friction (kinetic energy is wasted as heat and sound)
Light-emitting objects (light energy is wasted as heat)
Appliances intended for heating (heat energy is wasted as light)
Energy efficiency = useful power out / total power in
Some energy is always wasted from every device, efficiency
should always be less than 1 or less than 100%.
Kinetic Energy of an Object
1 1
( Energy ∈ joules )= ( Mass∈kg ) ( Velocity∈meter per second )2 E= M V 2
2 2
An 800kg car is driving at 2m/s. What is its energy?
½x800x(2x2) = 1,600J
A truck that weighs 1 ton is driving at 5m/s. What is its energy?
½x1000x25 = 12,500J
GPE of an Object
( Energy ∈ joules )=( Mass∈kg ) ( Height∈meters)(Gravitational force which equals 9.8 on earth)
E=MHG
A 6kg ball is being held 50 meters off the ground. What is the ball
GPE?
6x50x10 = 3,000J of gravitational potential energy.
A 40kg person is being held 8 meters off the ground. What is the
person's GPE? 40x8x10 = 3,200J of gravitational potential energy.
Principle of the Conservation of Energy
2
, Energy cannot be created nor destroyed; however, it may change
form.
Particle Theory of Matter
All matter is composed of particles
Different states of matter contain particles that are arranged
differently due to different forces that exist between particles
At higher temperatures particles move faster, and change the
state of matter.
Conduction
Heat transfer between objects through direct contact
Faster-moving particles collide with slower-moving particles,
transferring kinetic energy, increasing temperature
Continues until both objects reach thermal equilibrium (same
temperature)
Convection
Heat transfer between a surface and adjacent fluid (when heat is
added, hotter particles move upwards and the colder particles
move downward. This creates a convection
current, eventually heating all the fluid.
Radiation
Heat transfer through electromagnetic
waves
Can occur in a vacuum (no medium
required)
Occurs in all directions from a hot object
o The sun, microwaves, infrared radiation
Can refer to the emission of particles, such as alpha, beta, and
gamma radiation, which transfer heat energy through collisions with
other particles.
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Potential
Gravitational potential energy (GPE)
The potential of an object to do work because of its relative
position
o A ball held in the air
Elastic potential energy
The energy stored in an object when it is stretched or deformed
o A stretched rubber band
Chemical potential energy
The energy stored in the bonds between atoms, released as heat,
sound or light during chemical reactions such as burning
o Batteries
Nuclear potential energy
The energy stored in the nucleus of atoms, may be released
quickly as a nuclear explosion or controlled slowly in a nuclear
reaction
o Nuclear fission
Kinetic
Active energy
The energy that an object has because of its movement
o A thrown ball
Heat energy
The motions of atoms or molecules in a substance or object
o The sun
Sound energy
The vibration of particles, can be detected by the ear.
o A loud clap
Light energy
A form of electromagnetic radiation emitted by hot objects. It is
usually visible light
o A torch beam
Electrical energy
The energy generated by moving electrons
o Lightning
Mechanical energy
The energy of an object in motion and the energy that is stored
in objects by their position, combined GPE and active energy
o Car rolling down a hill (GPE and active energy)
1
,Energy Transformations
The conversion of energy from one form to another.
Battery: Chemical to electrical.
A swing: GPE to kinetic to GPE.
The sun: Nuclear to light and heat.
Energy Transfers
The movement of the same energy form from one object to
another.
A bowling ball hits another bowling ball.
Electricity going along a wire.
Heat going from a hot pan to a hand.
Energy Wastage and Efficiency
Wasted energy is energy that is not transferred or transformed
usefully. Common sources of wasted energy include:
Friction (kinetic energy is wasted as heat and sound)
Light-emitting objects (light energy is wasted as heat)
Appliances intended for heating (heat energy is wasted as light)
Energy efficiency = useful power out / total power in
Some energy is always wasted from every device, efficiency
should always be less than 1 or less than 100%.
Kinetic Energy of an Object
1 1
( Energy ∈ joules )= ( Mass∈kg ) ( Velocity∈meter per second )2 E= M V 2
2 2
An 800kg car is driving at 2m/s. What is its energy?
½x800x(2x2) = 1,600J
A truck that weighs 1 ton is driving at 5m/s. What is its energy?
½x1000x25 = 12,500J
GPE of an Object
( Energy ∈ joules )=( Mass∈kg ) ( Height∈meters)(Gravitational force which equals 9.8 on earth)
E=MHG
A 6kg ball is being held 50 meters off the ground. What is the ball
GPE?
6x50x10 = 3,000J of gravitational potential energy.
A 40kg person is being held 8 meters off the ground. What is the
person's GPE? 40x8x10 = 3,200J of gravitational potential energy.
Principle of the Conservation of Energy
2
, Energy cannot be created nor destroyed; however, it may change
form.
Particle Theory of Matter
All matter is composed of particles
Different states of matter contain particles that are arranged
differently due to different forces that exist between particles
At higher temperatures particles move faster, and change the
state of matter.
Conduction
Heat transfer between objects through direct contact
Faster-moving particles collide with slower-moving particles,
transferring kinetic energy, increasing temperature
Continues until both objects reach thermal equilibrium (same
temperature)
Convection
Heat transfer between a surface and adjacent fluid (when heat is
added, hotter particles move upwards and the colder particles
move downward. This creates a convection
current, eventually heating all the fluid.
Radiation
Heat transfer through electromagnetic
waves
Can occur in a vacuum (no medium
required)
Occurs in all directions from a hot object
o The sun, microwaves, infrared radiation
Can refer to the emission of particles, such as alpha, beta, and
gamma radiation, which transfer heat energy through collisions with
other particles.
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