Forces

• contact force have to be physically touching each other
• Non contact force doesn’t have to be touching each other
• Examples of contact forces are friction air resistance and tension
• air resistance is when air molecules collide with an object moving through them, causing it to slow down or change direction.
• what is a normal contact force

  Equal and opposite force
• Non contact force examples are magnetic electrostatic and gravitational
• Magnetic forces can be attractive or repulsive
• Scalar quantiles have 


  Magnitude and no direction
• Vector forces have

  Both magnitude and direction
• Newtons first law states that if there is no net force then the velocity will remain constant
• the SI unit for mass is kilogram (kg)
• The strength of a non-contact force depends on how close two objects are to one another
• Resultant force = sum of individual forces
• Gravitational forces act on all matter everywhere in the universe
• The resultant force is the total effect on an object due to all the forces acting upon it
• Newtons second law

  The force acting on an object is equal to the mass of that object times its

  acceleration, F = ma.
• Newtons third law

  For every action, there is an equal and

  opposite reaction.