Stress, Shear, and Survival

1. The Trap (Tensile Strength)

You are bound. Your first instinct is to pull your arms apart laterally. This is a mistake.

Duct tape has incredibly high Tensile Strength. When you pull apart, the Force ($F$) is distributed across the entire surface Area ($A$) of the tape. The Stress ($\sigma$) on any single fiber never gets high enough to break it.

2. The Weakness (Stress Concentration)

To escape, we must stop fighting the whole tape and fight one millimeter at a time. This is fracture mechanics.

If we apply the force to a tiny Area (the edge), the Stress skyrockets. Once the top fiber snaps, the load transfers to the next, creating a "Zipper" effect.

3. The Technique (Biomechanics & Impulse)

How do we create that "Edge Load" with our body? We use geometry and speed.

Conclusion

Duct tape is strong against Tension, but weak against Shear. The escape relies on physics, not brute strength.