Mastering physics:1.xtra practice Z-Google (horne Secure https://session.masteri
ID: 1655909 • Letter: M
Question
Mastering physics:1.xtra practice Z-Google (horne Secure https://session.masteringphysics.com/myct/itemView?assignmentProblemID-84 121697&offset-next; Extra Practice 2 Exercise 2.23 Enhanced with Solution Resources « previous | 7 of 74 | next s Exercise 2.23 - Enhanced with Solution Part A TVideo Tutor Solution, etext link, Worked Solutionll The human body can survive a negative acceleration trauma incident (sudden stop) if the magnitude of the acceleration is less than 250 m/s If yau are in an automobile accident with an initial speed of 100 km/h and are stopped by an airbag that inflates from the dashboard, aver what distance must the airbag stop you for you to survive the crash? = 1.54 m You may want to review (n pages 45-50) Submit My Answers Give Up For related problem-solving tips and strategies, you may want to view a Video Tutor Solution of Constant Correct IDENTIFY: Assume that the acceleration is constant and apply the constant acceleration kinematic equations. Set la xl equal to its maximum allowed value. SET UP: Let +x be the direction of the initial velocity of the car. az--250 m/s2 100km/h- 27.8ms EXECUTE: toz 27.8mys. ur 0. t . 1 2a#(z zo) gives .. 0-(27.8nn/s)',-1.54 m EVALUATE: The car frame stops over a shorter distance and has a larger magnitude of acceleration. Part of your 1.70 m stopping distance is the stopping distance of the car and part is how far you move relative to the car while stopping. Significant Figures Feedback: Your answer 1.53 m was either rounded differently or used a different number of significant figures than required for this part. ContinueExplanation / Answer
250 m/s^2 = max acceleration
Change in speed = 100 km/h - 0 = 100km/h
= 100*(1000/3600) = 27.78 m/s
We know that,
Change in speed = acceleration
time interval = t
250 = 27.78/t
t = 27.78/250 = 0.11 s
By using,
s = ut + 0.5at^2
s = 0 + 0.5*250*(0.11)^2 = 1.51 m
Answer