Forces

• A force is a push or pull that acts on an object and interaction with another object
• Forces can be measured using newtons (N)
• A scalar quantity has only magnitude ( size )
• A vector quantity has both magnitude ( size ) and direction
• Examples of scalar quantities are speed, distance, mass, time, temperature, and energy.
• Examples of vector quantities are velocity, displacement, acceleration, force, momentum, and work.
• Contact forces : Objects have to physically touch for a force to occur
• Non- Contact forces : Objects do not need to physically touch in order for a force to occur
• Examples of contact forces :

  Friction

  Air resistance

  Tension

  Normal Force
• Examples of non contact forces:

  Gravitational force - Force of attraction to the earth

  Electrostatic force - Between charged objects

  Magnetic Force - can attract or repulse
• The normal force is always perpendicular to the surface it acts on
• Weight = Mass x Gravitational Field Strength
• Work = Energy