forces :)

• Force


  A push or a pull
• Effects of a force

  • Cause an object at rest to start moving
  • Cause a moving object to speed up, slow down or change its direction of motion
  • Stop a moving object
  • Change the shape of an object
• Types of forces


  • Frictional force
  • Elastic spring force
  • Gravitational force
  • Magnetic force
• Frictional force

  The force that opposes motion
• Effects of frictional force

  • Slows down or stops moving objects as it acts in the opposite direction of motion
  • Greater frictional force between an object and a rough surface than between the same object and a smooth surface
• The amount of frictional force acting on an object does not depend on the surface area in contact
• Frictional force can be


  • Useful (helps us hold on to things, slow down or stop moving objects)
  • A problem (causes moving objects to slow down unnecessarily, causes objects to overheat or wear out)
• Ways to reduce frictional force

  1. Apply a lubricant on the moving parts of a machine

  2. Use rollers and wheels
• Elastic spring force


  The force exerted by springs when they are stretched or compressed
• Effects of elastic spring force

  • Allows a stretched or compressed spring to return to its original length when the applied force is removed
  • The more the force applied, the more the spring extends
• Gravitational force


  The force of attraction between objects
• Effects of gravitational force


  • Pulls all objects towards the centre of the Earth
  • Causes objects to have weight
• Weight


  The gravitational force acting on an object
• Weight varies from place to place, mass is the same regardless of location
• Magnetic force


  The force exerted by magnets
• Effects of magnetic force

  • Magnets can push or pull each other
  • Magnets can attract magnetic materials like iron and steel
• Magnetic force can pass through non-magnetic materials
• Mass


  A measure of the amount of matter in an object. It is a fundamental property of an object that does not change, regardless of where the object is located in the universe. Mass is typically measured in kilograms (kg).
• Weight


  A measure of the force exerted on an object due to gravity. It depends on both the mass of the object and the acceleration due to gravity. Weight is typically measured in newtons (N) or pounds (lb).