Physics P3 GCSE Revision Notes OCR (higher)

MEASURING SPEED

Speed = Distance
              Time

Stopping distances

Stopping distance = Thinking distance + Breaking distance

Factors that affect the thinking distance:

• Alcohol
• Mood
• Drugs
• Caffeine/Medicine
• Tiredness
• Speed
• Mobile Technology

Factors that affect the breaking distance:

• Friction
• If there is something wrong with the car
• Weather
• Speed

Forces and Acceleration

Newton's Laws of Motion

• If the force on an object is balanced, the object will continue to do what it is already doing.
  Eg. If Stationary, will remain stationary.
        If moving, it will continue to move.

• If the forces on an object are unbalanced, two things about the object can change.
  The speed may increase or decrease
  The direction of motion may change.

• If object A exerts a force on object B, then object B exerts an equal, but opposite force on object A.
  Eg. if you punch a wall, it will hurt your hand, just as much…