What are inertia and the interrail mass?

Interna is another way to phrase Newton’s First Law. Inertia means an object will stay stationary or continue moving at the same speed and direction (velocity) unless a resultant force is applied. While the interrail mass is a measure of how difficult it is to change the velocity of an object. And the inertial mass is defined as the ratio of the force needed to accelerate an object: the acceleration produced. Objects with a larger inertial mass will require a large force to produce a given acceleration than objects with a smaller inertial mass.