Inertia is the measure of an object's resistance to change. The greater the resistance the greater the inertia.

The idea of inertia was first presented by Galileo but was truly developed in Newton's First Law of Motion.

Newton's First Law of Motion states:

If an object is at rest it will remain at rest unless acted on by an outside force. But, if the object is in motion it will stay in motion, in a straight path, unless acted on by an outside force.

When an unbalanced force is applied to an object at rest the object changes its position and we say it has moved. Thus, motion is a change in position caused by a force and the distance the object moves is called displacement.

When an object is