Newton's First Law of Motion

• what is inertia


  the property of matter that causes a body to resist changes in its motion. the greater the mass, the greater the inertia
• Newton's first law of motion : the law of inertia


  the net force of an object is equal to the vector sum of all the forces acting upon said object
• Conclusions of Newton's First Law

  1. Objects at rest tend to stay at rest
  2. Objects in motion tend to stay in motion
  3. If the velocity of an object is constant, the net external force must be zero
  4. If the velocity of an object changes in magnitude, direction, or both, the change must have been caused by a net external force on the object