2. 1/2 points | Previous Answers My Notes Ask Your Teach Modern cars are designe
ID: 1658192 • Letter: 2
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2. 1/2 points | Previous Answers My Notes Ask Your Teach Modern cars are designed with a number of important safety features to protect you in a crash. These include crumple zones, air bags, and seat belts. Consider how a crumple zone (a section of the car that is designed to compress, like an accordion) and a seat belt work together in a head-on collision in which you go from a speed of 40.0 km/h to rest. (a) If you are not wearing a seat belt, then, in the crash, you generally keep moving forward until you hit something like the windshield. If you come to rest after decelerating through a distance of 11.0 cm after hitting the windshield, what is the magnitude of your average acceleration during the deceleration period? m/s (b lf, instead, you are wearing your seat belt, t keeps you in your seat, and you keep moving forward as the ront of the car crumpies like an accordion·if he compression of the crumple zone is 70.0 cm, what is the magnitude of your average acceleration during the deceleration period? 88.0 m/s2 Additional Materials eBookExplanation / Answer
Given,
u = 40 km/h = 11.11 m/s
a)s = 11 cm = 0.11 m
We know from eqn of motion
v^2 = u^2 + 2 a S
a = (v^2 - u^2)/2 S
v = 0; as u come to rest
a = (11.11^2 - 0^2)/2 x 0.11 = 561.06 m/s^2 (it should be negative as its deceleration)
Hence, a = 561.06 m/s^2(only magnitude)
b)We know from eqn of motion
v^2 = u^2 + 2 a S
a = (v^2 - u^2)/2 S
v = 0; as u come to rest
a = (11.11^2 - 0^2)/2 x 0.7 = 88.17 m/s^2 (it should be negative as its deceleration)
Hence, a = 88.17 m/s^2 (only magnitude)
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