acceleration

• What is acceleration?


  rate of change of velocity
• What is deceleration?

  negative acceleration

  
  

  slowing down
• Acceleration equation

  Acceleration = change in velocity/time
• What is uniform acceleration?


  the acceleration of an object is constant—it doesn't change
• How do you calculate uniform acceleration?

  Final velocity - initial velocity = 2 x acceleration x distance

  
  

  V2 - U2 = 2as
• Objects in free fall near the surface of the Earth experience

  9.8m/s acceleration
• What happens if an object has no force propelling it?


  Slows down and stops because of friction
• What does friction do?

  
  

  When does it happen?

  
  

  When does it increase?

  Act in opposite direction to movement

  
  

  Two surfaces in contact

  When an object passes through a liquid

  
  

  Increases with speed
• How do you travel at a steady speed?

  Driving force needs to balance the frictional forces
• What is drag?

  The resistance you get in a fluid

  
  

  eg air resistance
• How do we reduce drag?


  Keeping the shape of the object streamlined

  
  

  Object flows more easily
• What is terminal velocity?


  the greatest velocity a falling object reaches
• How is terminal velocity reached?


  Falling object sets off

  
  

  Gravity is more than frictional force slowing it down - it accelerates

  
  

  Speed increases = friction builds up

  
  

  Reduces acceleration

  
  

  Until frictional force is equal to accelerating force

  
  

  Reaches terminal velocity and falls at steady speed
• What does terminal velocity depend on?


  shape and area
• What forms can acceleration take?

  starting

  stopping

  speeding up

  slowing down

  changing direction

  
  

  on a free body diagram - arrows will be unequal