Newton's Law & Whiplash: How Headrests Protect Against Rear-End Collisions

Newton's first law (inertia): an object at rest stays at rest, an object in motion stays in motion unless acted upon by an unbalanced force.

In a rear-end collision, passengers' bodies initially at rest continue moving forward as the car accelerates. This causes neck hyperextension, leading to whiplash.

A head restraint supports the head and neck, preventing excessive backward motion and reducing hyperextension injury.