newtons laws of motion

• What is Newton's first law of motion?

  An object remains in a steady state unless acted upon
• What does Newton's first law state about a stationary object?

  If resultant force is zero, it remains stationary
• What happens to a moving object if the resultant force is zero?

  It continues moving at the same velocity
• What occurs if the resultant force on an object is not zero?

  Its velocity will change
• What must be balanced for a car to travel at a steady speed?

  Resistive forces and driving force
• What are the possible changes in velocity for an object?

  • Starts to move
  • Stops moving
  • Speeds up
  • Slows down
  • Changes direction
• What does Newton's second law state about acceleration?

  Acceleration is proportional to resultant force
• How is acceleration related to mass according to Newton's second law?

  Acceleration is inversely proportional to mass
• What does internal mass measure in an object?

  Difficulty in changing the object's velocity
• What are the characteristics of force pairs in Newton's third law?

  • Act on separate objects
  • Same size as each other
  • Act in opposite directions
  • Of the same type
• What does Newton's third law state about forces?

  Forces occur in equal and opposite pairs
• What is momentum?

  A property of all moving objects
• What does momentum depend on?

  Mass and velocity of an object
• What does the law of conservation of momentum state?

  Total momentum before equals after an event
• What is the range of human reaction times?

  Between 0.2 and 0.9 seconds
• What factors can affect reaction time?

  • Tiredness
  • Drugs
  • Alcohol
  • Distractions
• How can reaction times be measured?

  Using a computer or rule drop test
• What factors affect braking distance of a vehicle?

  • Speed of the vehicle
  • Road conditions
  • Conditions of brakes and tyres
• What can lead to increased braking distance?

  Less friction between tyres and road
• What happens when brakes are applied to a vehicle?

  A frictional force is applied to the wheels
• What does work done by frictional force do in a vehicle?

  Transfers energy from kinetic to thermal energy
• What happens to the temperature of brakes when energy is transferred?

  The temperature of the brakes increases
• What happens to energy and braking force as vehicle speed or mass increases?

  • Greater energy in kinetic energy store
  • More work needed to slow down
  • Greater braking force needed to stop
  • Greater stopping distance required