Forces

• Scalar quantities 


  Have a magnitude

  • Distance
  • Speed
• Vector quantities 


  Has a magnitude and a direction

  • Displacement
  • Velocity
• Displacement


  Overall distance from a fixed point
• Average velocity 


  Total displacement divided by time
• Velocity 


  The speed of an object in a particular direction

  • Vector quantity
• Acceleration 


  The rate of change in velocity
• Kinetic energy 


  Energy the object has by being in motion
• Newton's first law 


  An object remains in motion unless and resultant force acts upon it
• Resultant force 


  A single force that has the same effect as 2 or more forces acting together
• Inertia 


  The tendancy of an object to continue in its current state unless acted on by a resultant force
• Newton's second law

  Force = mass x acceleration
• Newton's third law

  Whenever 2 objects interact, exert equal and opposite forces on each other
• Terminal velocity  

  At terminal velocity, an object moves at a steady speed and the resultant force is zero
• Deformation

  When a force acts on a object, the object may change shape by bending, stretching or compressing
• Elastic deformation 


  When the force is removed it's reversed
• Plastic deformation 


  Not fully reversed when the force is removed
• Extension 


  Happens when an object increases in length
• Compression 


  Happens when an object decreases in length
• Hookes law


  Force exerted = extension x spring constant