1. Chapter 12 Work and Energy
Section 4
Conservation of Energy
p. 400

2. Understand the laws of thermodynamics
Objectives
Understand the laws of thermodynamics
Evaluate the effectiveness of perpetual motion

3. I. Energy Transformations
A. PE can become KE and KE can become PE
B. Mechanical energy can change into other forms (explains why a bouncing ball will stop)
II. Law of Conservation of Energy
A. 1st Law of Thermodynamics- Energy can neither be created or destroyed
Conservation of Energy

4. B. System may be open or closed
1. Open- an exchange occurs in
the space that surrounds
2. Closed- energy flow in and out
is negligible
C. Entropy
2nd Law of Thermodynamics
2. All things tend towards disorder

5. III. Efficiency
A. Not all work is useful (or work you
intended)
B. Efficiency is a ratio of useful work
output to work input
Efficiency= useful work output/work input
C. Perpetual Motion machines are
impossible because no machine is
100% efficient
D. Machines need energy input to keep
going

6. Bring in supplies for project Calculation WS Study for Test!
Homework
Bring in supplies for project
Calculation WS
Study for Test!