3.4: Newton's Law of Inertia

Simply put, things tend to keep on doing what they're already doing. Objects in a state of rest tend to remain at rest. Only a ________ will change that state.

force

Objects continue to move by themselves. Forces are needed to overcome any _________ that may be present and to set objects in motion initially. Once the object is moving in a force-free environment, it will move in a straight line _____________.

friction, indefinitely

Newton's first law, usually called the ______________, is a restatement of Galileo's idea that a force is not needed to keep an object moving.

law of inertia

The law of inertia provides a completely different way of viewing ______ from the ancients.

motion

Newton's first law states that every object continues in a state of rest, or of uniform speed in a straight line, unless acted on by a _______ net force.

nonzero