Question
Most of the electricity in the power grid is generated by powerful turbines spinning around. Why don’t these turbines slow down from the work they do moving electrons?
Final Answer
Because something else is doing work on the turbines, such as the wind for wind turbines, water for hydroelectricity, or steam from the burning of fossil fuels or the heat of nuclear fission.
Solution video
OpenStax College Physics for AP® Courses, Chapter 19, Problem 6 (Test Prep for AP® Courses)
vote with a rating of
votes with an average rating of
.
Prev
Video Transcript
This is College Physics Answers with Shaun Dychko. These turbines that are spinning around would slow down due to the work they are doing on moving electrons but they don't because there's something else in turn doing work on the turbines. So in the case of wind turbines, there's the wind that's doing work on the wind turbines and I guess you could ask what's doing work on the wind then and that's ultimately coming from the Sun, the energy from the Sun is causing temperature differences in the air to result in different air pressure in one place versus another and then wind is created by air flowing from high pressure to low pressure; you talk about water doing work on the turbines in the case of hydroelectricity... again this comes from the Sun ultimately because the Sun is what makes water evaporate and then turn into clouds which then rains and this is how the water got its high gravitational potential energy by coming down in the form of rain at a high position on the river and then flowing downhill through the turbine of the hydroelectric plant. Or there's steam from a fossil fuel or a nuclear reactor that is doing work on the turbines.