PHYSICS

• Galilean Conceptions


  Vertical Motion, Horizontal Motion, and Projectile Motion
• Scientists and philosophers have been trying to answer the question "Why do objects move?" even before 300 B.C.
• Aristotle's attempt


  Based on inductive-deductive reasoning, accepted for centuries
• Galileo Galilei challenged the Aristotelian view of motion through his actual and thorough experiments
• Aristotle's view on motion

  Natural motion: object will move and return to natural state based on material or composition

  Violent motion: object requires external force to move
• Aristotle's view on projectile motion

  Object thrown at angle is given an "impetus" - a force or energy that permits it to move, until impetus is lost and object falls to ground
• Galileo disproved Aristotle's claims and believed motion can be described by mathematics and changes in physical variables like time and distance
• Galileo's findings from experiments

  • An object in uniform motion will travel distance proportional to time

  A uniformly accelerating object will travel at speed proportional to time factor

  An object in motion, if unimpeded, will continue to be in motion; external force not necessary to maintain motion
• Horizontal motion


  An object in motion, if unimpeded, will continue to move without external force
• Vertical motion

  In absence of resistance, objects fall at same rate regardless of weight; object encountering resistive force will slow down and reach uniform motion
• Projectile motion


  Combination of uniform horizontal motion and uniformly accelerated vertical motion; object continues to move without applied force
• Uniform motion


  Object moving at constant velocity
• Constant acceleration motion


  Object traveling with varying velocity, may be speeding up, slowing down, or changing direction

  Acceleration = change in velocity / change in time

  SI unit is m/s^2
• Newton's Three Laws of Motion


  Explain why things behave the way they do

  Galileo's concept of inertia - objects tend to maintain initial state of motion

  
• Law of Universal Gravitation

  Every mass attracts another mass, with force directly proportional to product of masses and inversely proportional to square of distance
• Momentum


  Quantity of motion an object possesses, calculated as mass x velocity

  Conservation of momentum: in closed system, total momentum remains constant before and after collision/interaction

  Momentum is a vector quantity with both magnitude and direction

  SI unit is kg·m/s
• Impulse


  Change in momentum of object resulting from force applied over time, equal to force x time interval
• Learning Activity - Output 2


  Think of ideas showing how things move according to Newton's laws

  2. Draw/cut scene showing pushes, pulls, objects at rest

  3. Add color and details to show Newton's laws in action
• Law of Inertia
• Law of Acceleration
• Law of Interaction