Physics term 2

• Stationary


  No forces acting on object
• Accelerating


  More drive than drag
• Constant velocity


  Balanced drag and drive
• deacceleration


  More drag than drive
• Average speed = distance / time
• Force = mass x acceleration
• 
  

  acceleration = change in velocity / time taken
• velocity-time graph


  =

  
• distance-time graph


  :

  
• Scalar quantity

  • Only size not direction

  distance, mass, time, speed
• Vector quantity

  • Size and direction

  velocity, force, acceleration
• weight = mass x gravitational field strength
• stopping distance = thinking distance + brake distance
• How to find distance travelled in velocity-time graphs


  :

  
• Terminal velocity

  • at the start, the object accelerates downwards due to the force of gravity
  • as the object's speed increases, frictional forces such as air resistance or drag increase
  • at terminal velocity, the weight of the object due to gravity is balanced by the frictional forces, and the resultant force is zero
• Elastic


  object that returns to original shape when deformed
• Inelastic


  object that doesn't returns to its original shape when deformed
• Springs constant

  Force applied on a spring is directly proportionate to extension
• force = springs constant (k) x extension
• Density


  How much mass a substance has per unit of its volume
• density = mass / volume
• Pressure


  force per unit of area
• pressure = force / area
• Density experiment (regular shapes)

  1. find the mass of the object using a balance
  2. find the volume (length x width x height)
• Density experiment (irregular shapes)

  1. find the mass of the object using a balance
  2. place the object in water filled eureka can with measuring cylinder under sprout to find the volume
• Improvements to density experiment

  • Larger volume of objects
  • Find mean mass of objects
• Pressure in fluids

  The deeper you get the higher the pressure as water above is pushing down
• Pressure in fluids = height x density x gravitational field strength
• Gas pressure

  1. Gas molecules are in constant random motion inside a container
  2. Gas molecules collide/hit/bump into the walls of the container
  3. These collisions exert a force on the wall of the container
  4. Billions of the collisions together exert a larger force over an area of the container wall
  5. Pressure = Force/Area so gas molecules exert gas pressure by exerting a force over an area
• Absolute zero

  A state where there is no kinetic or thermal energy in particles

  • -273 celcius
  • 0 kelvins
• Kelvins = Celsius + 273

  Celsius = Kelvins - 273
• Factors affecting gas pressure

  • Temperature (temp inc -> pressure inc as more and stronger collisions)
  • Concentration (concentration inc -> pressure inc as more particles packed closely)
  • Volume (volume dec -> pressure inc as more particles in one metre squared)
• pressure x volume = constant (inversely related)
• P1 x V1 = P2 x V2
• P1 / T1 = P2 / T2
• Solar system


  System of planets revolving around the sun
• Galaxy


  Collection of billions of stars
• Milky way


  Earths galaxy
• Universe


  Scattered with galaxies
• Factors that effect gravitational field strength

  • Mass of planet
  • The distance away from core of the planet