25) What Is Another Name for the Line X = 0?

Grade
1) What is meant by the grade of a highway?
2) How might the grade of a highway influence the prices set by trucking companies to haul freight over the route?
3) Why are residential roads higher in the middle than at the curb?
4) What is considered to be the required minimum grade from the center of a residential road to the curb?
5) What is the generally accepted maximum grade for wheelchair ramps?
6) What is the maximum grade that an adhesion railroad can climb?
7) In the world of railroading, what is “dispatchable adhesion”?
8) How is the coefficient of wheel/rail adhesion calculated?
9) How has locomotion adhesion been improved over the last decades?
10) What are some of the steepest adhesion railroads in the world and where are they located? (give us one and leave the others for classmates!)
11) What two types of transportation are frequently called cable cars?
12) How do the San Francisco cable cars work?
13) How does a rack-and-adhesion railway work?
14) Where is the world’s highest cog railway?
Pitch
15) How steep does a roof have to be to be considered “pitched”?
16) How does “roof pitch” differ from “algebraic slope”?
17) What distinguishes a “salt box” house?
18) Why are roof lines different in New England and the Southwest?
19) About how steep is the average residential staircase?
Slippery Slopes
20) About how steep is the angle of the slope for “Extreme Skiers”?
21) In the US, about how steep is a green, beginners’ slope?
22) In the US, about how steep is a blue, intermediate slope?
23) In the US, about how steep is a black, expert slope?
24) I can ski a double black diamond slope at home. I can’t wait to ski one in Colorado! Is this wise? Why?