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Homework Help: How would you solve this.

  1. Mar 4, 2006 #1
    How would you solve this..........

    Calculate the carrying capacity (number of cars passing a given point per hour) on a freeway with three lanes (in one direction) using the following assumptions: the average speed is 90 km/h. the average length of a car is 6.0m, and the average distance between cars should be 65m.

    ANS: 3800/hr.

    I'm really stuck at this question. Somebody please help, we are currently studying velocity and acceleration in Physics.
  2. jcsd
  3. Mar 4, 2006 #2


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    Homework Helper

    The car which is at 90 km distance from the given point would just pass. All the other cars, closer than that farthest one woud obviously pass, too. One car occupies 6 + 65 m length. How many cars are then there in 90 km lenght of one lane?

  4. Mar 5, 2006 #3
    Another one............

    Thank you very much i got the first one. Physics isn't my strong point because i might not really good with word problems.

    A woman driving her car at 50 km/h approaches an intersection when the traffic lights turns yellow. She knows that the yellow ligh last only 2.0s before turning to red. and she is 30 m away from the near side of the intersection. Should she try to stop or should she make a run for it? The intersection is 12m wide. and her car's maxium deceleration is - 6.0 m/s*s. also her car takes 7.0 s to accelerate from 50 km/h to 70 km/h. Ignor the length of her car and her reaction time.
  5. Mar 5, 2006 #4


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    Staff Emeritus
    Science Advisor
    Gold Member

    You need to use some kinematic equations. Can you apply the correct ones?
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