physics

• Momentum


  The quantity of motion that an object has
• Momentum


  • Dependent upon two variables: how much stuff is moving and how fast the stuff is moving
• Momentum


  Equal to the mass of the object times the velocity of the object
• Momentum is directly proportional to an object's mass and directly proportional to the object's velocity
• Units of momentum


  Mass units times velocity units, standard metric unit is kg*m/s
• Momentum


  • A vector quantity, fully described by both magnitude and direction
• Direction of momentum vector


  Same as the direction of the velocity vector
• Momentum of an object at rest is 0
• Both mass and velocity are equally important in determining the momentum of an object
• An object accelerates when there is a change in velocity (going fast or slowing down) or a change in direction (moving in a circle)
• An object does not accelerate (no acceleration) when the object is moving with a constant velocity
• If an object is slowing down, then its acceleration is in the opposite direction of its motion
• Motion diagrams


  Indicate the positions of the car at regular time intervals
• Motion diagrams for an amusement park ride

  • moving with constant velocity
  • accelerating
  • moving with constant velocity
  • accelerating
  • accelerating
• Both cars have a constant velocity
• Free-Fall


  When the only force acting on the object is the Force of Gravity alone, regardless of its initial motion
• Free-Fall


  • It is not touching any other objects; hence objects thrown upward or downward and those released from rest from a certain height are all considered freely falling
  • There is no air resistance (Neglecting air resistance)
• Acceleration due to gravity (g)

  On earth, g=9.8 m/s²
• The acceleration due to gravity, g, is different on different planets and moons
• When an object is in Free-Fall, the acceleration is constant
• Uniformly Accelerated Motion


  An object in Free-Fall is an object experiencing Uniformly Accelerated Motion
• All objects, regardless of mass, will have the same acceleration due to gravity
• On earth, the acceleration due to gravity is not the same for each location
• When we look at a specific location, the acceleration due to gravity is constant and therefore we can use the UAM equations
• The acceleration due to gravity varies from location to location globally, but we use the standard gravity with a value of 9.8 m/s2 downward or g=-9.8 m/s
• An acceleration of 9.8 m/s² means that the object will increase its velocity by 9.8 meters per second each second
• An object that is thrown upward slows down at the rate of 9.8 m/s2 as the force of gravity is pulling it down until it will momentarily stop (V=0) when it reaches its highest point then it starts downward just as if it had been dropped from rest at that height
• The distance covered by an object in free fall is equal to the height (h)
• Formulas for free fall

  1. V₁ = V₁ + gt

  2. t = V₁- Vig

  3. vf = Vi²+2gh

  4. H: Vit + 2 gt²