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What is the magnitude of the average force that acts on the car during the impact?

The National Transportation Safety Board is testing the crashworthiness of a new car. The 2200 kg vehicle, moving at 13 m/s, is allowed to collide with a bridge abutment, which stops it in 0.43 s. What is the magnitude of the average force that acts on the car during the impact?

Public Comments

1. F = ma a = (Vf - Vi) / T F = m(-Vi) / T F = (2200kg)(-13m/s) / (.43s) F = -66511.6 N Since your answer needs to be a magnitude, then the force is positive (+ 66511.6 N).
2. Impact = change of momentum Impact: I=F_avg * _delta_t (t=0.43s in this case) Change in momentum: _delta_P = m * _delta_V _delta_ means the change in.. (something) so _delta_V means the change in the velocity after the impact so, delta_V= V_final - V_initial (final velocity is 0 in this case because it stops) F_avg * _delta_t = m * _delta_V F_avg * (0.43) = (2200) * (-13) F_avg = -66511.63 N (since it has a velocity of +13m/s, the force that stops it should be in the opposite direction which is the negative direction)