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Section 1.5What is Negative Acceleration?For our purposes decreasing speed while a car is traveling forward slowing down.What would a graph of braking distance vs. initial speed look like?

http://youtu.be/_zZXMDSROOkReal-World Connection: Stopping Distance

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http://www.gcse.comTotal Stopping Distance

Perception Distance= the distance you travel while identifying a situation+Reaction Distance= the distance you travel from the time you identify a hazard and decide to brake +Braking Distance= the distance you travel from the time you first apply the brakes to a full stop

Sample table of data collectedWhat would a graph of braking distance vs. initial speed look like?

Claim and EvidenceClaim: An automobile can be moving forward during negative acceleration.Evidence: What evidence can you provide to support this claim?v = 10 m/sd = 30 mt = 0.9 sAdditional Distance: v=d/t -> d=v*t -> d=10*0.9= 9 m (Thinking Distance)

Total Stopping Distance = Thinking Distance + Braking DistanceTotal Stopping Distance = 9 m + 30 m = 39 m14Practice: Physics to Go #4An automobile traveling at 10 m/s requires a braking distance of 30 m. If the driver requires 0.9 s reaction time, what additional distance will the automobile travel before stopping? What is the total stopping distance, including both the reaction distance and the braking distance?v = 10 m/sd = 30 mt = 0.9 sAdditional Distance: v=d/t -> d=v*t -> d=10*0.9= 9 m (Thinking Distance)

Total Stopping Distance = Thinking Distance + Braking DistanceTotal Stopping Distance = 9 m + 30 m = 39 m15What Do You Think Now?What factors must you consider to determine if you will be able to stop in the distance between you and the animal to avoid hitting it?HomeworkStudy Guide: Questions 1-7