introduction

• scalar quantaties

  • mass
  • energy
  • distance
  • time
• scalar have magnitude only
• vector quantities

  • displacement
  • weight
  • force
• vector - direction and magnitude
• contact forces are when objects are touching
• non-contact forces are when objects are not touching
• gravity is the force of attraction between all masses
• the force of gravity close to earth is due to the gravitational field around the planet
• the mass of an object is the amount of matter it contains and is constant
• weight is the force acing on an object due to gravity
• the weight of an object depends on the gravitational field strength and is directly proportional to mass
• when more than one force acts on an object these forces can be seen as a single force this is called resultant force