Which statement best describes the law of inertia?

Enhance your trauma care skills with the Platinum Trauma Exam. Use flashcards and multiple-choice questions with hints and explanations. Prepare now!

Multiple Choice

Which statement best describes the law of inertia?

Inertia is the tendency of an object to resist changes in its motion. If no net external force acts on an object, its velocity stays constant—so a moving object keeps moving in the same direction at the same speed. The statement that a moving object remains in motion until acted on by another force directly expresses this idea, making it the best description of inertia. A related piece of the same principle is that objects at rest stay at rest unless a net force starts them moving, but describing motion captures the essence in a single line. The other options conflict with inertia: forces aren’t needed to keep something moving, and forces can change an object’s speed.

Inertia is the tendency of an object to resist changes in its motion. If no net external force acts on an object, its velocity stays constant—so a moving object keeps moving in the same direction at the same speed. The statement that a moving object remains in motion until acted on by another force directly expresses this idea, making it the best description of inertia. A related piece of the same principle is that objects at rest stay at rest unless a net force starts them moving, but describing motion captures the essence in a single line. The other options conflict with inertia: forces aren’t needed to keep something moving, and forces can change an object’s speed.

More practice questions