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Chapter 4
The Classical Mechanics Explanation
of Motion (Dynamics): Newton’s
Laws of Motion
Introduction: Our approach
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Force
Inertia
Mass
Force & acceleration
Nature of Interaction
More
Force
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As the cause of changes in motion
Contact and non-contact forces
A vector quantity
Simple free body diagrams to represent forces
on an object
– Exercises
– Tutorials
Inertia
• The revolutionary idea of inertia: constant
velocity motion is the new “natural motion”
• Newton’s First Law of Motion
• Examples, Activities
– Inertial reference frames
– “non-accelerating”
• Newton’s First Law as a test
• Inertia as a name for the validity of the First
Law
Mass
• Mass as a measure of the amount of inertia
– when there is a non-zero net force on the object
– in contrast to “the quantity of matter”
– in contrast to weight
From Force to Acceleration
• The revolutionary idea of force tracking with
acceleration
• Newton’s Second Law
– net force on object
– mass of object
– acceleration of object
– vector equation
• The “Newtonian Project”
The Nature of Interaction
• Forces among objects come in pairs, equal and
opposite
• Precise statement of Newton’s Third Law
– Implications and examples
• The Third Law as a test of inertial frames
More…
• A closer look at weight and normal force
– Definitions
– Examples
• Problem Solving with Newton’s Laws
– General approach
– Examples
the end