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• Speed


  Distance / Time
• Calculating speed


  S = d / t
• Calculating time

  T = d / s
• Distance-time graphs


  • Straight line - consistent speed
  • Steeper - faster
  • Horizontal - not moving
  • Curved - speed is changing
• Force


  A push or pull that can cause objects to change speed, squash or squeeze
• Forces


  • Can work through objects being in contact or at a distance
  • Measured in Newtons (N)
  • Reaction only happens when in contact with a solid
  • More than one force can act on an object at the same time
• Resultant force

  1. Always state the size & the direction

  2. If unbalanced, the object accelerates in the direction of the resultant force

  3. If 0, the forces are balanced and the object does not accelerate
• Friction


  Caused by a moving object against another surface, acts in the opposite direction to the movement<|>Smooth surfaces or lubricants can reduce friction
• Upthrust

  A supporting force acting on an object caused by a fluid, always acts in an upward direction<|>The weight of a sinking object will always be greater than the upthrust, the upthrust and weight of a buoyant object are balanced
• Air resistance


  Caused by a solid object rubbing against the air, objects moving quickly experience more air resistance<|>Objects with a greater surface area experience less air resistance, these can be described as streamlined or aerodynamic
• Mass


  A measure of how much matter makes up an object, measured in kilograms, the same everywhere in the universe
• Weight


  A force caused by the pull of an object's gravity, measured in Newtons, can vary depending on the gravitational field strength
• Weight = Mass x Gravitational field strength (W=mg)
• Solar System

  • Made up of planets, moons, and other phenomena that orbit the Sun
  • Planets are kept in orbit due to the gravitational pull of the Sun, the shape of each orbit is an ellipse
  • Planets further away from the Sun take longer to orbit
• Earth's rotation and tilt

  Rotates once every 24 hours, 23° tilt causes seasons
• Eclipses


  1. Occur when the Earth, Sun, and Moon line up and block each other

  2. Solar eclipse when the Moon blocks light from reaching the Earth

  3. Lunar eclipse when the Earth blocks light from reaching the Moon
• Heliocentric model - the Sun is at the centre of the universe
• Geocentric model - the Earth is at the centre of the universe