The inertia of two objects with equal masses is the same. This means that they will resist changes in their motion to the same extent. For example, if you try to push two objects with equal masses, they will accelerate at the same rate. This is because the force required to accelerate an object is directly proportional to its mass. So, if two objects have the same mass, then the force required to accelerate them will be the same.

The inertia of an object is also related to its momentum. Momentum is the product of an object's mass and velocity. So, if two objects have the same mass, then their momentum will be the same if they are moving at the same speed.

The inertia of an object is a fundamental property of matter. It is what gives objects their resistance to changes in their motion. Inertia is also what makes it possible for objects to move in a straight line at a constant speed without any external force acting on them.