An air tugger is lowering a load and the cable slows, then pulls the slack through the snatch block, allowing the load to drop a short distance. What is this situation commonly referred to as?

• A. Dynamic loading
• B. Impact loading
• C. Overrunning load
• D. Shock loading

Answer: (D)

When a load is being moved with slack in the line and that slack is suddenly taken up, the load can drop a short distance and then the line becomes taut again. At that moment the mass must decelerate rapidly, creating a sudden, short-lived spike in tension in the line and equipment. This rapid surge in force is called shock loading. The key idea is the abrupt change in velocity and the resulting high peak force, even though the average load might be lower. This is why the situation described is classified as shock loading.