In a motor vehicle collision where a vehicle struck a tree, which is the best indicator of potential injury?

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Multiple Choice

In a motor vehicle collision where a vehicle struck a tree, which is the best indicator of potential injury?

Speed at impact is the best indicator of potential injury because it determines how much energy the vehicle—and thus the occupants—must absorb during deceleration. The energy that must be dissipated is proportional to the square of speed (E ∝ v^2), so even small increases in speed lead to disproportionately larger forces on the occupants when the crash stops them. The result is greater deceleration (delta-V) and a higher risk of serious injury. Other factors like the car’s size, the tree’s diameter, or the vehicle’s mass don’t directly capture how much energy must be absorbed in the crash. Mass matters only in combination with speed, and even a heavier car at a given speed can produce similar injury potential to a lighter one; without knowing impact speed, predicting injury risk is less reliable.

Speed at impact is the best indicator of potential injury because it determines how much energy the vehicle—and thus the occupants—must absorb during deceleration. The energy that must be dissipated is proportional to the square of speed (E ∝ v^2), so even small increases in speed lead to disproportionately larger forces on the occupants when the crash stops them. The result is greater deceleration (delta-V) and a higher risk of serious injury.

Other factors like the car’s size, the tree’s diameter, or the vehicle’s mass don’t directly capture how much energy must be absorbed in the crash. Mass matters only in combination with speed, and even a heavier car at a given speed can produce similar injury potential to a lighter one; without knowing impact speed, predicting injury risk is less reliable.

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