contact and N contact forces + more

• Contact force


  A force that is caused by two objects interacting and touching each other
• Non-contact force


  A force that acts between objects without them having to touch
• All forces are either contact or non-contact forces
• When two objects interact, there is a force produced on both objects
• Interaction pair


  A pair of forces that are equal and opposite and act on two interacting objects
• This is basically Newton's Third Law
• Examples of contact forces

  • Motion, air resistance, tension in ropes, normal contact force
• Examples of non-contact forces

  • Magnetic force, gravitational force, electrostatic force
• Vectors have magnitude and direction
• Force is a vector quantity
• Scalar quantity


  A physical quantity that has only magnitude, not direction
• Velocity is a vector, but speed is a scalar quantity
• Vectors are usually represented by an arrow, the length shows the magnitude and the direction shows the direction
• When analysing forces, it is important to consider the direction as well as the magnitude
• Gravitational force is the force of attraction between masses
• Mass


  The amount of 'stuff' in an object, the same value anywhere in the universe
• Weight


  The force acting on an object due to gravity, varies with location
• Weight and mass are directly proportional
• Increasing the mass of an object increases its weight
• Resultant force


  The overall force acting on an object or point
• A free body diagram shows all the forces acting on an isolated object
• Work


  The transfer of energy when a force moves an object through a distance
• Scale drawings can be used to find the magnitude and direction of resultant forces
• An object is in equilibrium if the forces on it are balanced
• Forces can be split into horizontal and vertical components
• Elastic deformation


  When an object can return to its original shape and length after a force is removed
• Inelastic deformation


  When an object does not return to its original shape and length after a force is removed
• Work is done when a force stretches or compresses an object, transferring energy to the elastic potential energy store
• There is a limit to the amount of force that can be applied before the extension is no longer proportional to the force