Monday 17 December 2012

Sunday 16 December 2012

Forces

Forces give an object the energy to move, stop or change its direction.
 
 
Types of forces:
  1. Contact forces: There's a contact between two objects, two people or a person and an object.
  • To push: to move an object forwards.
  • To pull: to move an object backwards.
 
      2. Non-contact force: no contact takes place.
 
  •  Gravitya force that attracts an object to another.
         It is the force that pulls everything towards the Earth's surface.




  • Magnetism: It is the force the magnets produce.
             


Tuesday 11 December 2012

Simple machines and complex machines.


Complex Machines.



 Complex machines are two or more simple machines working together.

e.g. A car is a complex machine; there are many simple and complex machines working together and at the same time.
 
 

Simple Machines

Simple Machines
A simple machine is a  device for altering a force.


Simple Machines: lever, bar, pulley, inclined plane, screw, wheel, axle and wedge.

1. Lever:: A lever moves on a fulcrum
  
      2.   Wheel:    A wheel spins around an axle.
 
      
3.   Pulley: A pulley is a wheel with a rope.
 
 
 
4. Inclined plane:
 
 
 
 
5. Wedge
 
 

6. Screw 

7. Axle