Explanation

Newton's first law of motion is also called as Law of inertia.

• Inertia is the ability of a body by virtue of which it opposes a change.
  
• According to Newton’s first law of motion, an object will remain at rest or in uniform motion in a straight line
• unless acted upon by an external force.
  • The inertia of rest: When a body is in rest, it will remain at rest until we apply an external force to move it. This property is called inertia of rest.
  • The inertia of motion: When a body is in a uniform motion, it will remain in motion until we apply an external force to stop it. This property is called inertia of motion.