Types of Force (Edexcel International AS Maths) : Revision Note

Types of Force

What is a force?

• A force is a vector quantity, it has both magnitude and direction

• A force is a push or a pull on an object

• A force is measured in Newtons

• In A level mathematical models, forces act at a single point called a particle which occupies a single point in space

What types of force are used in mechanics?

• Weight is the effect of mass and gravity, it always acts downwards

• Tension is a pulling force, it always acts away from an object

• Thrust is a pushing force, it always acts towards an object

• Friction is a resistive force, it acts to oppose the motion of an object

• Every surface will produce a reaction force, it will always act perpendicular to the surface

Mass, Gravity and Weight

• Mass is a measure of the amount of matter in an object

  • Mass is a scalar quantity, measured in kilograms, kg

  • Mass is universal, it does not change based on location

• Gravity is the force by which a body (usually a planet or a star) pulls objects towards its centre

  • g is the acceleration due to gravity, measured in m s ^-2

  • On Earth, g is approximately 9.8 m s ^-2 , although its exact value varies with location

  • g is different elsewhere in the universe

• Weight is the product of mass and gravity, it is a force measured in Newtons

  • Weight is a vector quantity

  • Weight varies with location

  • Weight always acts vertically downwards towards the ground