Question

why do experts use one kind of explosive for steel columns and another for concrete columns? experts must put explosives in holes for steel columns but wrap explosives in mesh for concrete columns. steel is stronger than concrete, so it requires a more powerful explosive. experts have to blow up steel columns but use a special strong fabric to break apart concrete columns. steel is sharper than concrete, so it requires much more explosive.

Explanation:

To determine the correct answer, we analyze each option:

• Option 1: Describes the method of placing explosives (holes for steel, mesh for concrete), which relates to the different structures of steel and concrete columns requiring different explosive deployment methods. This makes sense as steel columns may need explosives placed in drilled holes, while concrete columns (with reinforcing mesh) may have explosives wrapped around the mesh.
• Option 2: Steel's strength doesn't directly mean it needs a more powerful explosive; the key is how the explosive is applied, not just power.
• Option 3: The description of using fabric to break concrete columns is incorrect; explosives, not fabric, are used.
• Option 4: "Sharpness" of steel is not a relevant factor for explosive requirements.

Answer:

A. Experts must put explosives in holes for steel columns but wrap explosives in mesh for concrete columns.