Fundamentals of Transportation/Grade/Additional Problems

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Additional Questions[edit]

  1. What is maximum grade a vehicle can travel, what effects it? Explain how to find maximum grade at a given speed. Explain what each variable means and how it contributes to figuring max grade.
  2. Why are A and C_D the only things need to calculate air resistance. → Because it is a crude approximation of aerodynamics. Real aerodynamics are of course complicated, but the additional detail does not sufficiently improve accuracy.
  3. If there were no heavy vehicles, would planners design roads with steeper grades? → Yes, they should. There has been discussion for a number of years for separate car and truck highways, since car-only highways would be cheaper and truck-only highways could avoid congestion. However additional rights of way would be required
  4. Define rolling resistance. Why is rolling resistance different for cars and trucks? What is the difference between rolling resistance and maximum grade?
  5. What is the relationship between available power and nominal power? Why do trucks use more of their nominal power than cars.
  6. What is the mass/power ratio used for?
  7. What happens if air resistance is larger than tractive effort force.
  8. What is maximum grade a road can have?
  9. What forces affect vehicle motion?
  10. What are two relevant parameters for passenger car, type P?
  11. Define F_r, F_a, F_t, F_g.
  12. If given a grade of 3%, should you use 0.03 or 3 in the equation?
  13. How does coefficient of rolling resistance vary between vehicles.
  14. What kind of safety factors are in these equations.