Seat belt retractor behavior — inertial locking mechanism Evaluate the statement: The seat belt will move out smoothly when pulled slowly, but it will lock when pulled quickly.

Introduction / Context:
Modern vehicles use inertia-reel (ELR) seat belt retractors that allow comfort during normal movements yet lock the belt during rapid deceleration or abrupt pulling. This question checks understanding of that safety mechanism.

Given Data / Assumptions:

• The retractor contains a spool, a spring, and an inertial locking device (ball or pendulum) or web-sensing mechanism.
• Normal slow extension should be smooth.
• Rapid pull simulates crash-like acceleration or sudden occupant motion.

Concept / Approach:
Inertia-sensing mechanisms engage a pawl with the ratchet on the spool when a threshold acceleration or web acceleration is detected, halting belt payout. This prevents excessive occupant excursion while permitting everyday comfort and minor movements when pulled gently.

Step-by-Step Solution:
Consider slow pull: inertial device not triggered; belt feeds smoothly.Consider fast pull or vehicle deceleration: inertial sensor engages; spool locks.Therefore, the given statement accurately reflects ELR function.

Verification / Alternative check:
User manuals describe the belt locking if pulled out rapidly or if the vehicle decelerates/tilts suddenly, confirming the statement.

Why Other Options Are Wrong:
'Disagree' would contradict well-known ELR behavior designed to meet safety regulations.

Common Pitfalls:
Testing on a slope can lock the belt unexpectedly due to angle-sensitive mechanisms; worn retractors may stick, but the design intent is as stated.

Final Answer:
Agree