Types of Forces (Edexcel IGCSE Physics)

• When a force acts on an object, the force can affect the object in a variety of ways
• The object could:
  • change speed
  • change direction
  • change shape

• The effects of forces on an object often depend on the type of force acting
  • The push force (thrust) of an engine can cause a car to speed up, whilst the force exerted by the brakes (friction) can cause it to slow down
  • The gravitational pull of the Sun on a comet causes the comet to change direction
  • When two opposing forces push on each end of a spring, the spring changes shape (it compresses)

The effects of different forces on objects

Forces can change the speed or direction of motion of an object, or even change its shape

• There are many types of force. Some examples include:
  • Gravitational (or weight) - the force between any two objects with mass (like the Earth and the Moon)
  • Electrostatic - the force between any two objects with charge (like a proton and an electron)
  • Thrust - the force pushing a vehicle (like the push from rocket engines on the shuttle)
  • Upthrust - the upward force on any object in a fluid (like a boat on the surface of a river)
  • Air resistance (or drag) - the force of friction between objects falling through the air (like a skydiver in freefall)
  • Compression - forces that squeeze an object (like squeezing a spring)
  • Tension - forces that stretch an object (like two teams in a tug-of-war)
  • Reaction force - the force between any two objects in contact (like the upwards force from a table on a book)

Several types of forces acting on different objects