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DO NOW
May 22, 2017
Have three questions that you have done with the
students in previous days to introduce this
material, or simply as a review.
1. 2. 3.
Focus Point: What Is a Reactive Engine?
Instructional Objectives:
• 1. Define jet propulsion.
• 2. Identify 2 families of jet
engines.
• 3. Describe the different
types of reactive engines.
May 22, 2017
Basic Principle of Jet Engine Operation
• Newton’s Third Law of Motion: For every
action there is an equal but opposite reaction.
Push
Moves In this
Direction
Are We Really Pushing
in An Opposite Direction?
• The answer is yes when you consider that to
push to the right you must also be pushing to
the left, otherwise you would move in that
direction.
Jet Engines Are Really
Reactive Engines
• “JET” is really a slang term for Reactive
Engines that use thrust as a propelling force.
• Reactive Engines are engines that move
forward because of a rearward discharge of
thrust.
Example of Reaction
• Basic Jet Engine
Reaction
Exhaust
Gasses
The Term “Jet Propulsion”
• Jet Propulsion is a propelling force (thrust)
generated in the direction opposite to the
flow of a mass of air, liquid or a gas escaping
at a high velocity through an opening called a
nozzle.
May 22, 2017
Summary:
• Instructional Objectives:
• 1. What is “Jet
Propulsion?”
• 2. Why is Newton's Third
Law so critical for jet
engines?
• 3. Give 4 examples that
use a reactive engine.