Final answer:
A V-shaped collapse occurs when the exterior walls of a structure collapse, characterized by the exterior walls moving outward and the upper parts falling inward.
Step-by-step explanation:
When the exterior walls of a structure collapse, this typically results in a V-shaped collapse pattern. This type of collapse is named as such due to the resulting shape post-collapse, which resembles the letter 'V'. This occurs when forces exerted leads to the exterior walls moving outward, causing the upper portions of the structure to fall inward, thereby forming a 'V' shape. This pattern contrasts with options like a pancake collapse, where building layers fall mainly vertically down due to failing support structures, or a lean-to collapse, which occurs when one wall or support remains while the rest of the structure falls down towards it.
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