[2.3] Laws of Motion

• ARISTOTLE


  Divided motion into two main classes: natural motion and violent motion.
• ARISTOTLE

  He asserted that natural motion proceeds from the “nature” of an object, dependent on the combination of the four elements (earth, water, air, and fire) the object contains. It could be either a straight-up or straight-down. On the other hand, violent motion results from pushing or pulling forces. It was an imposed motion, externally caused, and was imparted to objects.
• GALILEO GALILEI


  Concerned with how things move rather than why they move.
• ISAAC NEWTON


  Developed the famous laws of motion, which completed the overthrow of the Aristotelian ideas that had dominated the thinking of the best minds for nearly two millennia.
• ISAAC NEWTON

  He published the book entitled, Philosophiæ Naturalis Principia Mathematica (Latin for Mathematical Principles of Natural Philosophy) which contained the foundations of the three Laws of Motion.
• LAW OF INERTIA


  Every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero net force.
• INERTIA


  Describes an object’s tendency to resist changes in its state of motion.
• MASS

  • “Sluggishness” of an object in response to any changes in its state of motion.
  • The amount of matter in an object, and does not change regardless of location.
• WEIGHT


  The force of gravitational attraction that the earth exerts on objects.
• LAW OF INERTIA

  “Every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero net force.”
• LAW OF ACCELERATION

  “The acceleration of an object is directly proportional to the net force acting on an object, is in the direction of the net force, and is inversely proportional to the mass of the object.”
• LAW OF INTERACTION

  “To every action, there is always an opposed equal reaction.”
• ACTION-REACTION FORCES


  Every force is part of an interaction between two objects.