A steam turbine is a device in which high-pressure steam enters the turbine and causes blades to spin. The spinning blades have mechanical energy. Which best describes what happens in this system?

High-pressure steam transfers energy to the turbine blades as it expands and pushes against them. Some of the steam’s thermal energy is converted into mechanical work, making the blades spin. Energy is transformed, not created or destroyed, so choices C and D describe the process incorrectly.

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