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Distance traveled if a driver hits the brakes

  • Thread starter Naryeth
  • Start date
  • #1
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Homework Statement


A person driving her car at 51 km/h approaches an intersection just as the traffic light turns yellow. She knows that the yellow light lasts only 2.0 s before turning to red, and she is 30 m away from the near side of the intersection (Fig. 2-29). The intersection is 15 m wide. Her car's maximum deceleration is -6.0 m/s2, whereas it can accelerate from 51 km/h to 70 km/h in 5.7 s. Ignore the length of her car and her reaction time.

If she hits the brakes, how far will she travel before stopping (in meters)?

Homework Equations


I don't know. As far as I can tell, I have two unknowns here.

The Attempt at a Solution


Lost here. As far as I can tell, all I know is that V0 = 51km/h (or 14.2m/s) and a = -6.0m/s2. Any help is appreciated, thanks in advance.
 

Answers and Replies

  • #2
PhanthomJay
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As far as I can tell, I have two unknowns here. All I know is that V0 = 51km/h (or 14.2m/s) and a = -6.0m/s2. Any help is appreciated, thanks in advance.
You also know that the car comes to a stop.
 

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