What determines the amount of energy a rope can absorb when arresting a fall?

• A. Anchor strength
• B. Rope construction
• C. Edge protection
• D. Rope elongation

Answer: (D)

Rope elongation is what sets how much energy the rope can absorb during a fall arrest because the rope behaves like a spring when the fall is stopped. As the rope extends under load, it stores energy equal to the area under its force–extension curve. The more the rope can stretch before reaching critical force, the more energy it can absorb, which helps keep the arrest force manageable. Dynamic ropes are designed to elongate significantly under load, so they can soak up more of the fall energy than static ropes, which stretch very little and transfer more energy into peak forces. Anchor strength and edge protection affect safety margins and damage risk, and rope construction influences durability and performance, but the inherent energy-absorption capacity during arrest is driven mainly by how much the rope can elongate.