1. Glencoe: Chapter 5 Sections 1 and 2 Pages 128-133 Pages 135-143
Energy
Glencoe: Chapter 5 Sections 1 and 2
Pages
Pages

2. Work and Energy Energy – the ability to do work
1. Work – a force that causes a change in motion (force across a distance)
 Example – pushing a car or riding a bike
2. Energy is measured in Joules (J)

3. Work and Energy
B. Potential energy (PE) – stored energy, energy of position
1. There are two types of potential energy
a. Gravitational potential energy – energy of position
- Examples  a boulder on a cliff, an apple hanging on a tree

4. Work and Energy
B. Potential energy (PE) – stored energy, energy of position
b. Elastic potential energy – stored energy due to compression or stretching
- Examples  a stretched rubber band, a wound up spring
2. Energy that is waiting to be released

5. Work and Energy
C. Kinetic energy (KE) – energy of a moving object due to its motion
 Energy of motion
1. Depends on the velocity and mass of the
moving object

6. Work and Energy
C. Kinetic energy (KE) – energy of a moving object due to its motion
2. Faster and more massive = more kinetic energy

7. Work and Energy D. Other forms of energy
1. Kinetic molecular energy  energy of moving atoms and molecules
2. Chemical energy
 energy released in chemical reactions
 energy stored in the food you eat

8. Work and Energy 3. Nuclear energy  nuclear reactions (fission,
fusion), the sun
4. Solar energy  sunlight, electromagnetic waves
5. Electrical energy  electricity, movement of charged ions
and electrons

9. Conservation of Energy
A. The Law of Conservation of Energy – Energy cannot be created or destroyed, but can only change form.
1. Potential energy changes to Kinetic energy as a ball
rolls down a hill (stored energy changing slowly to
energy of motion.)
2. This transformation occurs slowly, NOT all at once.
3. At the top of the hill all the energy is potential, at the
bottom of the hill all the energy is kinetic (until the ball
stops rolling)
4. Some energy is lost to friction and heat, but it is not
destroyed

10. Conservation of Energy
Energy only changes form

11. Conservation of Energy