Windmills Are NOT Like Dams

The video explains how windmills extract kinetic energy from wind, contrasting it with dams that use potential energy. It discusses the relationship between wind speed and energy extraction efficiency, highlighting that the optimal efficiency is achieved when the wind is slowed to one-third of its initial speed. This results in an overall efficiency of 59.259%. The video also notes that real-world windmills are more complex, and actual efficiency may vary due to engineering considerations.

What type of energy is extracted by a windmill?

• Chemical energy

• Potential energy

• Thermal energy

• Kinetic energy

How is the maximum possible energy extracted from the wind calculated?

• By assessing the windmill's material

• By determining the temperature difference

• By calculating the difference between initial and final kinetic energy

• By measuring the height of the windmill

If the outgoing wind speed is half of the incoming speed, what fraction of the initial energy is extracted?

• 1/4

• 1/2

• 1/3

• 3/4

What is the overall efficiency when the wind is slowed to one-third of its initial speed?

• 88.88%

• 75%

• 59.259%

• 56.25%

Why does reducing the wind speed below one-third result in lower overall efficiency?

• It extracts more energy but from less wind

• It allows more wind to pass but extracts less energy

• It increases the windmill's mechanical wear

• It causes the windmill to stop completely