PPLGS Module 6

How will frost on the wings of an airplane affect takeoff performance?

• Frost will disrupt the smooth flow of air over the wing, adversely affecting its lifting capability.

•  Frost will change the camber of the wing, increasing its lifting capability.

• Frost will cause the airplane to become airborne with a higher angle of attack, decreasing the stall speed.

Every physical process of weather is accompanied by, or is the result of, a

• movement of air.

• pressure differential.

• heat exchange.

What causes variations in altimeter settings between weather reporting points?

• Unequal heating of the Earth's surface.

• Variation of terrain elevation.

• Coriolis force.

When there is a temperature inversion, you would expect to experience

• clouds with extensive vertical development above an inversion aloft.

• good visibility in the lower levels of the atmosphere and poor visibility above an inversion aloft.

• an increase in temperature as altitude increases.

The most frequent type of ground or surface-based temperature inversion is that which is produced by

•  terrestrial radiation on a clear, relatively still night.

• warm air being lifted rapidly aloft in the vicinity of mountainous terrain.

• the movement of colder air under warm air, or the movement of warm air over cold air.

Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high?

• Smooth air, poor visibility, fog, haze, or low clouds.

•  Light wind shear, poor visibility, haze, and light rain.

• Turbulent air, poor visibility, fog, low stratus type clouds, and showery precipitation.

The wind at 5,000 feet AGL is southwesterly while the surface wind is southerly. This difference in direction is primarily due to

• stronger pressure gradient at higher altitudes.

• friction between the wind and the surface.

• stronger Coriolis force at the surface.

 What is meant by the term dew point?

• The temperature at which condensation and evaporation are equal.

•  The temperature at which dew will always form.

• The temperature to which air must be cooled to become saturated. 

The amount of water vapor which air can hold depends on the

• dew point.

• air temperature.

• stability of the air.

Clouds, fog, or dew will always form when

• water vapor condenses.

• water vapor is present.

• relative humidity reaches 100 percent.