Unit 2 Exam Study Guide

Fill in the blank. Leonardo da Vinci's flying machine, the ornithopter, was an invention that _______.

• flapped its wings like a bird

• was powered by steam engines

• used jet propulsion

• was designed for underwater travel

Which of the following best explains why wind tunnels are used in testing the design of aircraft?

• To conduct a test flight of an aircraft without effects of weather

• To test scale models of airfoils and aircraft

• To study why an airplane crashes or malfunctions

• To correct any human errors made during manufacturing

Which of the following represents a contribution Greek myths made to civilization today?

• Scientific concepts related to flight

• Early flight techniques

• Inspiration for human flight

• Earliest designs of airplanes

Which concept(s) best illustrates the mechanics of flying a hot air balloon? Select all that apply.

• Buoyancy

• Density

• Gravity

• Weight

What does the camber of an airfoil refer to?

• The curve of the wing

• The straight line that connects the leading edge to the trailing edge of the wing

• The distance between the top and bottom of the wing

• The symmetry of the wing

What is the purpose of the burner of a hot air balloon?

• It lowers the weight of the basket by warming the balloon.

• It warms the air just outside the balloon causing it to rise.

• It warms passengers at high altitudes.

• It heats the air inside the balloon causing it to rise.

What part of a bird most resembles the propeller on an aircraft?

• Beak

• Wings

• Head

• Tail

Hot air balloons rise because warm air in the balloon ______, lifting the balloon.

• evaporates

• starts to cool

• becomes less dense

• becomes heavier

For modern day gliders, what does Bernoulli’s Principle demonstrate?

• An airplane’s wing is an obstacle to the oncoming air. As the air meets the wing, its path widens

• The speed of the air is faster as it hits the top of the wing causing an increase in pressure and creating lift. This permits flight of the glider.

• Air slows down as it hits the top of the wing, which increases pressure and creates drag. This permits the flight of the glider.

• Air moves faster over the top of the wing than air moving below the wing. This creates an area of low pressure on top of the wing, which lifts the glider up.

Why is air density important when using hot air balloons?

• As air inside the balloon gets warmer, the density of the air in the balloon decreases, causing it to rise.

• It is a measure of how much air there is surrounding the balloon to help support it.

• It is a measure of how much drag there is surrounding the balloon to help stabilize it.

• Density of cold air is less than hot air. The cold air presses against the balloon on the outside, pushing it up.