Motion and Forces

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Motion and Forces
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Force

• A push or a pull
• Cause an object to start moving, stop moving, or
  change direction

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Balanced and Unbalanced Forces
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Unbalanced Force

• Cause an object to start moving, stop moving, or
  change directions
• Unbalanced forces will change an objects motion

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Unbalanced Forces

• Net Force the overall force on an object after
  all the forces on an object are added up

1 2 1
1 2
1

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3
2
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Balanced Forces

• Equal forces acting on each other in opposite
  directions
• Balanced forces acting on an object will not
  change the objects motion

1 0 1
1 0
1
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Newtons 1st Law of Motion
An object at rest will remain at rest and an
object that is moving at a constant velocity
will remain at a constant velocity unless acted
upon by an unbalanced force
(Inertia)
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Inertia

• Tendency of an object to resist change in its
  motion
• Ex. If you are not wearing a seat belt when a car
  crashes inertia continues to carry you forward

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What affects Inertia?

• Mass the greater the mass the greater the inertia
• Question what has greater inertia a Honda Civic
  going 30 k/ph, or a Truck at the same speed?

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Friction

• Is opposite resistance to an objects direction in
  motion
• Depends on 2 factors
• The two surfaces involved
• How hard are the surfaces pushing against each
  other

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Types of Friction

• Sliding - solids over each other
• Rolling - when an object rolls over a surface
• Fluid- objects moving through fluids (liquid or
  gases)

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Weight vs. Mass

• Weight is a measure of the force of gravity on an
  object, mass is a measure of the amount of matter
  in an object
• You have the same mass on the Moon as Earth, but
  different weights

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Gravity

• Gravity is a force between any two objects, the
  force of gravity is related to the mass of the
  objects, and their distance from each other

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Force in Fluids

• Force is applied to a fluid causing pressure
  increase in a fluid
• The heart applies pressure to the blood forcing
  it through your vessels, blood flow in the body
  requires force