Newton's Laws of Motion

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Newton's Laws of Motion
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Newtons First Law of Motion

• An object at rest tends to stay at rest and an
  object in motion tends to stay in motion with the
  same speed and in the same direction unless acted
  upon by an unbalanced force.

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• In other words, an object will keep doing
  whatever its doing (sitting still or moving)
  unless an unbalanced force acts on it.
• Example Your skateboard will stay lying in the
  driveway until someone moves it. And, if your
  skateboard suddenly hits a curb and stops short,
  you will keep moving until something stops you!

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• Newtons 1st Law of Motion is also known as the
  Law of Inertia.
• Inertia is an objects tendency to resist a
  change in motion.
• The greater an objects mass, the greater its
  inertia, and the larger the force needed to
  overcome the inertia.

• Which vehicle would take longer to stop?

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Examples of Newtons 1st Law The Law of Inertia
Think about what you have learned about Newtons
1st Law, the Law of Inertia. With a partner,
think of an example to share.
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Newtons 1st Law and You
Because of inertia, objects (including you)
resist changes in motion. When the car going 80
km/hour is stopped by the brick wall, your body
keeps moving at 80 km/hour.
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Newtons 2nd Law
F m x a
Force mass x acceleration
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Newton's 2nd Law of Motion

• The greater the force applied to an object, the
  more the object will accelerate.
• It takes more force to accelerate an object with
  a lot of mass than to accelerate something with
  very little mass.

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Newton's 2nd Law of Motion

• The greater the force, the greater the
  acceleration.
• The greater the mass, the greater the force
  needed for the same acceleration
• Calculated by F ma
• (F force, m mass, a acceleration)

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Examples of Newtons 2nd Law
Think about what you have learned about Newtons
2nd Law. With a partner, think of an example to
share.
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Newtons 3rd Law

• For every action force, there is an equal and
  opposite reaction force. (Forces are always found
  in pairs.)
• Athlete pushes bar upwards.
• Bar pushes the athlete downwards.
• Bowling ball pushes pin to the right.
• Pin pushes bowling ball to the left.

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Newtons 3rd Law
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Newtons 3rd Law
Inside rocket, fuels are burned in the engine,
producing hot gases. The hot gases push against
the inside tube of the rocket and escape out the
bottom of the tube. As the gases move downward,
the rocket moves in the opposite direction.
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Examples 3rd Law
Think about what you have learned about Newtons
3rd Law. With a partner, think of an example to
share.