If she hits the brakes, how far will she travel before stopping?

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SUMMARY

The discussion focuses on calculating the stopping distance of a car traveling at 56 km/h with a maximum deceleration of -5.6 m/s². Given that the car is 30 m from the intersection and the yellow light lasts for 2.0 seconds, the key kinematic equation to determine the stopping distance is derived from the formula: \(d = v_i t + \frac{1}{2} a t^2\). The car will travel a distance of approximately 15.56 meters before stopping, which confirms that the driver should stop rather than attempt to cross the intersection.

PREREQUISITES
  • Kinematic equations for uniformly accelerated motion
  • Understanding of speed conversion from km/h to m/s
  • Basic principles of deceleration and acceleration
  • Knowledge of distance, time, and speed relationships
NEXT STEPS
  • Study the kinematic equations in detail, focusing on \(d = v_i t + \frac{1}{2} a t^2\)
  • Learn how to convert speed units from km/h to m/s accurately
  • Explore real-world applications of deceleration in automotive safety
  • Investigate the effects of reaction time on stopping distances
USEFUL FOR

This discussion is beneficial for physics students, automotive engineers, and anyone interested in understanding vehicle dynamics and stopping distances in traffic scenarios.

rakesh44
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Homework Statement


A person driving her car at 56 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). Should she try to stop, or should she make a run for it? The intersection is 15 m wide. Her car's maximum deceleration is -5.6 m/s2, whereas it can accelerate from 56 km/h to 70 km/h in 4.2 s. Ignore the length of her car and her reaction time. If she hits the brakes, how far will she travel before stopping?


Homework Equations


can someone at least give me a formula that i can use to find the answer??
thankss
 
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Refer any textbook and list the kinematic equations.
 

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