Which of the following best summarizes the essence of inertia?

Inertia is a fundamental concept in physics that relates to an object's resistance to changes in its state of motion. It specifically refers to the tendency of an object to maintain its current state, whether that is at rest or in uniform motion, unless acted upon by an external force.

The correct answer captures this essence by highlighting that an object at rest will remain at rest due to its inertia, reflecting the principle outlined in Newton's first law of motion. This law states that an object will not change its motion unless a force is applied to it. Understanding inertia is crucial for analyzing how objects behave in different scenarios, such as why we feel a jolt when a car suddenly accelerates or decelerates.

Options that describe acceleration or the ability to float do not accurately capture this fundamental concept. Similarly, stating that a force is required to move an object refers to Newton's second law of motion, which builds on the concept of inertia but does not define it directly. Thus, the second option perfectly encapsulates the definition and essence of inertia.