Fundamentals of Transportation/Grade/Additional Problems
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- 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.
- Why are and 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.
- 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
- Define rolling resistance. Why is rolling resistance different for cars and trucks? What is the difference between rolling resistance and maximum grade?
- What is the relationship between available power and nominal power? Why do trucks use more of their nominal power than cars.
- What is the mass/power ratio used for?
- What happens if air resistance is larger than tractive effort force.
- What is maximum grade a road can have?
- What forces affect vehicle motion?
- What are two relevant parameters for passenger car, type ?
- Define , , , .
- If given a grade of 3%, should you use 0.03 or 3 in the equation?
- How does coefficient of rolling resistance vary between vehicles.
- What kind of safety factors are in these equations.