Energy and Environment II Answers in Red

QUIZ #4

1. Consider the surface winds from the global viewpoint. Which of the following latitudes generally have strong winds (S), and which generally have weak winds (W)?

Latitude	Answer
0 degree (equatorial region)	Weak
15-20 degrees N and S	Strong (trade winds)
About 30 degrees N and S	Weak
50-60 degrees N and S	Strong

2. Complete the sentence:

The coast of Washington is windy because of the temperature difference between the air over the sea and over the land. During the day, air over land heats up relative to the air over the sea. The denser air over the sea pushes inland -- this is the onshore wind. At night, a reverse process occurs. See Figure 7.9, p. 273, in text. An additional factor is the relatively strong prevailing winds from the SW at the latitude of Washington.

3. Make a plot showing how the lift and drag coefficients of an airfoil vary with angle of attack. Clearly construct and label your plot.

See Figure 7.28, p. 286 in text

4. How does the cost of electrical energy from wind turbine projects compare with that from hydroelectric and natural gas power plants?

Type	Cost
Wind	About 5 cents/kwh (highest)
Hydro	About 1-2 cents/kwh (lowest)
Natural Gas	About 3 cents/kwh (medium)

Also OK: Figure 7.44, p 303, in text shows hydro and natural gas about the same for the cost of the electricity generated.