Motion

• Motion


  Change in position of any mass with respect to time
• Distance


  Total length covered by an object
• Displacement


  Change in the position of an object or the shortest distance between the initial and final position of an object
• Speed


  How fast the object is moving, expressed as distance/time, SI unit: m/s
• Velocity


  How fast and where the object is moving, expressed as displacement/time, SI unit: m/s
• Acceleration


  Change in the velocity of an object per unit time, SI unit: m/s2
• Inertia


  Ability of an object to resist motion
• Aristotle


  • Greek philosopher whose ideas formed the basis of many concepts at the time
  • 2 Main Classes of Motion: Natural Motion (Vertical Motion) and Violent Motion (Horizontal Motion)
• Natural Motion (Vertical Motion)


  • Merely the rising and falling, an object moves and returns to its natural state based on its material and composition
• Natural Motion


  • A stone thrown upward will fall back to the ground because its element is the Earth
  • Smoke rises in the air because it is its natural place
• Violent Motion (Horizontal Motion)


  • Requires a push or pull to maintain its horizontal motion, no motion will take place when there is no mover or an outside force
• Galileo Galilei


  • Italian astronomer and mathematician who made fundamental contributions to the sciences of motion, astronomy, and the strength of materials and to the development of scientific method
  • Vertical Motion: In the absence of resistance, objects would not fall depending on their weight but in the time of fall
  • Horizontal Motion: An object in motion, if unimpeded, will continue to be in motion, an external force is not necessary to maintain the motion
• On downward-sloping planes, the force of gravity increases a ball's speed while on an upward-slope the force of gravity decreases the ball's speed
• If smoother plane was used, the ball rolled up the opposite plane closer to the initial height. Friction affects the motion of the ball
• An object in uniform motion will travel a distance that is proportional to the time it will take to travel
• A uniform accelerating object will travel at a speed proportional to some factor of time
• An object in motion, if unimpeded, will continue to be in motion: an external force is not necessary to maintain the motion
• Projectile Motion


  • Aristotle believed that the motion of an object is parallel to the ground until it is the object's time to fall back into the ground
  • It is a combination of the uniformly accelerated motion in the vertical and the uniform motion in the horizontal motion
• Projectile Motion


  • When shooting a ball, the ball does not need an outside force to keep it moving once the ball is released
• Free Fall


  When a body falls under the sole influence of gravity with an approximate acceleration of 9.8m/s2 regardless of the body's masses
• Types of Free Fall

  • Objects thrown upward - positive initial velocity
  • Objects thrown downward - negative initial velocity
  • Dropped - zero initial velocity
• After every second, a ball rolling down an inclined plane increases its speed by the same value
• The acceleration of the rolling ball increases as the inclined plane becomes steeper
• When the inclined plane was position vertically, the rolling ball has the maximum acceleration
• Uniform or Constant Acceleration


  Steady, incremental additions of velocity evenly proportionate to time
• Positive Velocity


  Indicates that the object moves toward the positive direction
• Negative Velocity


  Indicates that the object moves toward the negative direction
• Positive Acceleration


  Indicates that the object is speeding up
• Negative Acceleration


  Indicates that the object is slowing down
• Sir Isaac Newton


  • Expanded Galileo's work and came up with his three Laws of Motion
• Law of Inertia


  • States that an object at rest will remain at rest while an object in motion will continue moving unless acted upon by an unbalanced force
  • Mass is proportional to inertia
• Inertia of Rest


  • A big stone on the ground
• Inertia in Motion


  • Riding a bike, the bicycle will continue moving as you step on the pedal, and once you stop pedaling the bike will eventually stop