Forces

Forces

1. THRUST IS..

   • upward or forward force
   • used for propellers, rocket engines (etc)
   • it can be used for handheld objects

2. FRICTION IS...

   • Slows down a moving object
     • A rough surface increases friction
     • a smooth surface reduces friction

3. GRAVITATIONAL FORCE IS...

   • the pull of attraction between two masses
     • examples...
       • the attraction between a book and a person is small
       • the attraction between the earth and an object is large
   • what is weight?
     • gravitational force between an object and the earth
       • weight is measured in newtons
     • equation to work out the weight
       • weight= mass times 10N/kg
   • what is mass?
     • mass is the 'amount of matter' or stuff somthing contains
       • mass is measured in kg.

4. BALANCED FORCE IS..

   • equal in size but opposite in direction
     • if forces on an object are balanced then..
       • an object that is not moving stays still
       • an object that is moving continues to move at the same speed and in the same direction

5. Upthrust IS...

   • upward force experienced in a liquid
     • upthrust is caused by water being pushed out the way
   • upthrust is decided by the volume of the object and density of the liquid

6. MAGNETIC FORCE IS..

   • when magnets exert a pull or pushing force
     • two same sides, i.e a north side and north side will exert a pushing force
     • two opposite sides, i.e a north side and south side will exert a pull force
   • when some materials, like metal, experience a magnetic force when a magnet is near.