Final answer:
Personal fall arrest systems must safely stop a fall by minimizing force on the user's body and maintaining a safety margin, similar to how seat belts protect car passengers during a crash.
Step-by-step explanation:
Personal fall arrest systems are designed to safely stop a fall before the user strikes the ground or a lower level. When stopping a fall, these systems must minimize the force on the user's body and maintain a sufficient margin of safety. They do this through the use of various components such as a full-body harness, a deceleration device, and an anchor point, which work together to gradually decelerate the user and distribute the impact of the fall over a larger area of the body.
For example, in a scenario like a car crash, seat belts act in a similar way to personal fall arrest systems by decelerating the passengers over a brief period and reducing the force exerted on them. This is analogous to how fall arrest systems must operate, providing a safe and controlled stop after a fall. Therefore, the primary goal of personal fall arrest systems is to effectively and safely stop a fall, ensuring the protection and well-being of the user during and after the event of a fall.