Objects at rest STAY at rest'''

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Newtons 1st Law

• Objects at rest STAY at rest...

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Newtons 1st Law
an object will keep its velocity constant!

• Objects at rest STAY at rest or
• objects in motion STAY in motion...

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Newtons 1st Law

• Objects at rest STAY at rest, or
• objects in motion STAY in motion...

UNLESS acted upon by unbalanced forces (or NET
force)
OR
IF acted upon by balanced forces. (no net force)
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So, What is Inertia?

• Law of Inertia
• Tendency for an object to maintain its state of
  motion
• Measured by the amount of mass of an object
  (INERTIA MASS)

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What are forces?
Forces are any push or pull on an object.

• ALL FORCES are interactions between TWO objects.
• for example- the force of gravity on an apple
  is really the interaction between _________ and
  the apple!

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What are forces?
Forces are any push or pull on an object.

• TYPICAL DEFINITIONS abbrev.
• FORCES
• 1. Gravity the Earth pulling an object down
  Fgrav
• 2. Normal Force a surface pushing an object
  Fnorm
• 3. Friction any resistance to motion Ffric
• (sliding, rolling, air resistance)
• 4. Tension a string or cable pulling an object
  Ften
• ALL FORCES are measured in units of Newtons (N)
  in metric system or
• pounds (lbs) in the English system

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Comparison of Mass vs. Weight
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Comparison of Mass vs. Weight
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Comparison of Mass vs. Weight
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Comparison of Mass vs. Weight
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Comparison of Mass vs. Weight
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Comparison of Mass vs. Weight