Newton

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Newtons First and Second Laws of Motion

• 12.2

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I. Scientists

• Aristotle, Galileo and Newton all worked on
  concepts of force and motion
• Aristotle- incorrectly proposed that force is
  required to keep an object moving at constant
  speed, this error held back progress in the study
  of motion for almost two thousand years.

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• Galileo- helped correct misconceptions about
  force and motion
• Concluded that moving objects not subjected to
  friction or any other force would continue to
  move indefinitely
• Newton- built on the work of Galileo and defined
  force and mass. He introduced his laws of motion
  in Principia- his book

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II. Newtons First Law

• The state of motion of an object does not change
  as long as the net force acting on the object is
  zero
• An object at rest remains at rest unless an
  unblanced force acts on it
• ex kicking a soccer ball
• Inertia- the tendency of an object to resist a
  change in motion

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Upon impact, the test dummy continues forward
until it hits something inertia
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III. Newtons Second Lawacceleration net force
F mass m

• The acceleration of an object is equal to the net
  force acting on it divided by the objects mass
• Ex the more force you apply to throwing a ball
  the more the ball accelerates
• This law also works on forces in opposite
  directions
• Ex seatbelts in cars- explain
• pg 367 Math Practice 1-3

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IV. Weight and Mass

• Weight- the force of gravity acting on an object
• Weight mass x acceleration due to gravity
  (9.8m/s2)
• mass is a measure of the inertia of an object
  weight is a measure of the force of gravity
  acting on an object

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Planet Multiply your weight by New weight
Mercury 0.4
Venus 0.9
Earth 1
Mars 0.17
Jupiter 2.5
Saturn 1.1
Uranus 0.8
Neptune 1.2
Moon 0.17