key concepts

• speed

  • sound in air - 330 m/s
  • walking - 1.5 m/s
  • running - 3 m/s
  • cycling - 6 m/s
  • car - 25 m/s
  • train - 55 m/s
  • aeroplane - 250 m/s
• scalars - magnitude

  • speed
  • temperature
• vector - direction and magnitude

  • velocity
  • displacement
• contact forces - two objects make physical contact

  • tension
  • friction
  • air resistance
• non contact forces - without making physical contact

  • weight
  • electromagnetism
• newton's first law

  • an object will stay stationary / constant motion unless acted upon by another force
• newton's second law

  • force = mass x acceleration
• newton's third law

  • every action has it's equal opposite reaction
• safety features - seat belts

  • stop you flying out of your seat
  • stretches / increases time taken for the bodies momentum to reach 0
  • reduce forces acting on the body
• safety feature - air bags

  • soft surface to collide with during crash
  • increase the time taken for the bodies momentum to reach 0
  • reduces forces acting on the body
• safety features - crumple zones

  • car crumples in a controlled way
  • increases time taken for passengers momentum to reach 0
  • reduces forces acting on passengers
• stopping distance - total distance the car travels from when the driver first notices an obstruction to when cars stop

  • thinking distance + braking distance