U2C1

Vocabulary

When we use energy, it does NOT disappear

• energy transfers from object to object

• A car engine burns gasoline, converting the chemical energy in gasoline into mechanical energy

• Solar cells change radiant (light) energy into electrical energy

Law of Conservation of Energy

Energy•causes interactions

•ability to do work or cause change

potential energy

•stored energy

potential energy

kinetic energy

•energy in motion

kinetic energy

14-1

What is energy?What is energy?red text

pages 292-293pages 292-293

Energy•causes interactions

•ability to do work or cause change

energy

1. kinetic energy -the energy of motion

ANYTHINGANYTHING moving has kinetic energy

• Show me your spirit fingers

kinetic energy

1. kinetic energy - motion energy– Depends on mass and speed of object

different mass, same speeddifferent mass, same speed

20 kph20 kph 20 kph20 kph

mass, mass, KE KE

1. kinetic energy - motion energy– Depends on mass and speed of object

same mass, different speedssame mass, different speeds

20 kph20 kph

75 kph75 kph

speed, speed, KE KE

factors that effect kinetic energyfactors that effect kinetic energy

mass, KE speed, KE

2. potential energy- energy that is stored and held in readiness

ANYTHINGANYTHING ready and waiting to move has

potential energy

2. potential energy- stored energy

ANYTHINGANYTHING ready and waiting to move has potential energy

2. potential energy- stored energy

PE = weight x heightPE = weight x height

PE = weight x heightPE = weight x height

height, height, PE PE

PE = weight x heightPE = weight x height

weight, weight, PE PE

factors that effect potential energyfactors that effect potential energy

height, PEmass, PE

What are the 2 types of energy?What are the 2 types of energy?

kinetic energy -the energy of motion

potential energy -energy that is stored and held in readiness

factors that effect kinetic & potential energy

mass, KE speed, KE height, PEmass, PE

mass, KE

100 lbs 150 lbs

speed, KEWhen does the car have the most KE?:

At 25 mph

At 55 mph

At 100 mph

height, height, PE PE

mass, PE

175 lbs175 lbs150 lbs150 lbs

energy can be transferred

• potential energy can be transferred into kinetic energy and vice versa

kinetic & potential energy

height , PE

height , PE

speed , KE

speed , KE

potential energy can be transferred into kinetic energy and vice versa

mass, KE speed, KE height, PEmass, PE

1. Are there any points at which the kinetic energy of the yo-yo is zero?

Points 1, 5 and 9

2. At what points is the potential energy a minimum?

Point 5

3. At what points is potential energy a maximum?

Points 1 & 9

4. What is the energy doing?•energy is transferring from potential energy to kinetic energy and vice versa

•As the yo-yo goes down,

PE and KE •As the yo-yo goes up,

PE and KE

energy transfers

Light

flashlight

Change in shape (pupil got smaller)

eye