Energy Transfer - OBJECTIVES Introduce the concept of the...

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2 OBJECTIVES Introduce the concept of the system energy and define its various forms. Discuss the nature of internal energy. Define the concept of heat and the mechanisms of heat transfer. Define the concept of work, including several forms of mechanical work. Introduce the energy balances, and the forms of energy transfer to or from a system including the energy associated with a flowing fluid. Define energy conversion efficiencies.
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Can exist in numerous forms such as kinetic, potential, electrical, magnetic, chemical, and nuclear, Their sum is the total energy, E of a system. The total energy, E of a system can be divided into: Macroscopic or external forms of energy : Those a system possesses as a result of its motion and elevation in a gravitational field with respect to some outside reference frame, such as kinetic and potential energy, respectively. Microscopic or internal forms of energy : Those related to the molecular structure and the molecular activity of a system. The sum of all the microscopic forms of energy is called the internal energy, U . 3 The macroscopic energy of an object changes with velocity and elevation.
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Total energy of a system Kinetic energy Kinetic energy per unit mass Potential energy Potential energy per unit mass Total energy of a system per unit mass
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5 Mass flow rate Energy flow rate
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