In a scenario with three vehicles at the same speed and the same distance from a barrier, which vehicle experiences the greatest force of impact?

In a scenario with three vehicles at the same speed and the same distance from a barrier, which vehicle experiences the greatest force of impact?

• A. SUV
• B. All the same
• C. Tractor-trailer
• D. Sports car

Answer: (C)

Impact force comes from how much momentum a vehicle has and how quickly that momentum is brought to a stop. If three vehicles hit a barrier at the same speed and stop over the same distance, they all experience the same deceleration (a = v^2 / (2d)). The force on each vehicle is F = m × a, so the vehicle with the greater mass experiences a larger force. The tractor-trailer has the greatest mass, so it undergoes the greatest force of impact in this scenario. The SUV and the sports car, being lighter, experience smaller forces even though they share the same speed and stopping distance.

Impact force comes from how much momentum a vehicle has and how quickly that momentum is brought to a stop. If three vehicles hit a barrier at the same speed and stop over the same distance, they all experience the same deceleration (a = v^2 / (2d)). The force on each vehicle is F = m × a, so the vehicle with the greater mass experiences a larger force. The tractor-trailer has the greatest mass, so it undergoes the greatest force of impact in this scenario. The SUV and the sports car, being lighter, experience smaller forces even though they share the same speed and stopping distance.