Newton's First Law says that an object at rest will remain at rest, and an object in motion will remain in motion unless it is acted on by an outside force. This is the law of__________.

inertia

velocity

momentum

gravity

inertia

inertia

The correct answer is "inertia."

To arrive at this answer, we can break down the question and analyze Newton's First Law. Newton's First Law states that an object at rest will remain at rest, and an object in motion will remain in motion unless it is acted on by an outside force. This concept is commonly known as inertia.

Inertia is a property of matter that describes its resistance to changes in motion. It can be thought of as the tendency of an object to resist changes in its velocity, whether it is at rest or already in motion. According to Newton's First Law, when no external force is applied to an object, its velocity remains constant.

Hence, the law mentioned in the question is the law of inertia.