Drag, Lift, Bernoulli & Windmills

In a windmill blade, lift is

• a(n) upwards/perpendicular force
• resistance
• not important
• None of the above

In a windmill blade, drag is

• upwards/perpendicular force
• resistance
• not important
• None of the above

According to Bernoulli's Principle, wind speed and wind pressure have a _________ relationship

• directly proportional
• inversely proportional
• not enough information
• None of the above

According to Bernoulli's Principle, when the wind speed is high, wind pressure is ________

• high
• low
• not enough information
• None of the above

According to Bernoulli's Principle, when the wind speed is low, wind pressure is ________

• high
• low
• not enough information
• None of the above

To generate lift, a blade is angled so the _________ pressure air moves under the blade.

• high
• low
• not enough information
• None of the above

The law which determines windmill's possible efficiency is called

• The Bernoulli Principle Law
• Betz's Law
• Windmill Efficiency Law
• None of the above

Betz's Law states that no windmill can capture more than ______ of the kinetic energy in wind to convert into electricity.

• 59.3%
• 53.9%
• 35.9%
• 39.5%

To move the windmill blades, the blades must be set at an angle so the _______ is greater than the ____________

• lift; drag
• drag; lift
• pressure; speed
• speed; pressure

According to Bernoulli's principle, by curving the blades, the wind is split so _______ speed wind travels above the blade and _________ speed wind travels below the blade. This causes more pressure ________ the blade generating _______.

• high; low; under; lift
• high; low; above; lift
• low; high; under; lift
• low; high; above; lift