Crash Dynamics Flashcards
7 cards from real ACTAR practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Crash Dynamics flashcards as text
What does the term 'delta-V' represent in vehicle collision analysis?
Answer: The change in velocity experienced by a vehicle during the collision event
Delta-V is the vector change in velocity a vehicle undergoes during the impact phase, a key metric for severity assessment and occupant injury evaluation.
When a vehicle understeers during a pre-crash avoidance maneuver, the front tires are operating:
Answer: At or beyond their lateral force capacity, causing the vehicle to push wide
Understeer occurs when front tire lateral forces are saturated, causing the vehicle to follow a path with a larger radius than the steering input commands.
In the context of a side-impact collision, the 'struck side stiffness' is generally lower than frontal stiffness because:
Answer: Vehicle door structures lack the longitudinal frame rails present at the front and rear
Vehicle doors and side panels lack the strong longitudinal frame rails and crumple zone design present at the front, making them structurally less stiff and leading to greater intrusion per unit energy.
Which of the following conditions would cause an analyst to OVERESTIMATE pre-impact speed when using skid mark analysis?
Answer: Using a drag factor that is too low
Using a drag factor that is too low underestimates the decelerating force, requiring a higher computed speed to produce the observed skid length, thus overestimating speed.
A vehicle traveling uphill on a grade of 5% has an effective drag factor that is:
Answer: Increased by 0.05 compared to level road
On an uphill grade, gravity adds resistance to braking, so the effective drag factor increases by the grade value (expressed as a decimal), e.g., f_eff = f + 0.05.
The term 'closing speed' in a collision context refers to:
Answer: The rate at which the distance between two approaching vehicles decreases
Closing speed is the scalar sum of the components of each vehicle's velocity directed toward the other, representing how quickly the gap between them closes.
In an energy-based reconstruction of a collision, which measurement of crush depth is considered the most critical input for accurate delta-V estimation?
Answer: Average crush depth across the damage profile
The Campbell model uses the average of multiple crush measurements across the damage zone to represent energy absorbed, making the average crush profile the most critical input.