Fundamentals of Transportation/Grade/Homework
Homework
[edit | edit source]1. Determine the maximum grade an empty tractor-trailer with a mass of 10000 kg can climb at a sustained speed of 75 km/h.
The frontal area (A) of the truck is 10 m2, the drag coefficient = 1.00 and the available power is 280 kW, ρ=1.2 kg*m−3, g = 9.81 m*sec−2
2. What is the maximum grade a bicycle can climb at a sustained speed of 12 km/h assuming the following:
- Rho = density of air (1.20 kg*m−3)
- g = 9.81 m*sec−2
- Mass (with bicyclist) = 100 kg
- Nominal Power = 1 kW
- Frontal Area (A) = 1 m2
- Drag Coefficient = 0.5
- Available power = 100 percent of nominal power
- Fr = 0.020 W
3. Bicyclists get tired. Assume the bicyclist slowly loses power (and thus velocity) going up the hill of the grade you just determined in question 2 above. If available power drops continuously from 100% to 0% over the course of the hour, to the nearest kilometer, how far does the bicyclist travel? (Use appropriate approximations.)