LN_Sec_14-4_one - POWER AND EFFICIENCY (Section 14.4)...

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POWER AND EFFICIENCY (Section 14.4) Today’s Objectives : Students will be able to: a) Determine the power generated by a machine, engine, or motor. b) Calculate the mechanical efficiency of a machine.
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READING QUIZ 1. The formula definition of power is ___________. A) dU / dt B) F v C) F d r / dt D) All of the above. 2. Kinetic energy results from _______. A) displacement B) velocity C) gravity D) friction
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POWER Thus, power is a scalar defined as the product of the force and velocity components acting in the same direction . Since the work can be expressed as dU = F • d r , the power can be written P = dU/dt = ( F • d r )/dt = F • (d r /dt) = F v If a machine or engine performs a certain amount of work, dU, within a given time interval, dt, the power generated can be calculated as P = dU/dt Power is defined as the amount of work performed per unit of time .
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POWER (continued) Using scalar notation, power can be written P = F v = F v cos θ where θ is the angle between the force and velocity vectors. In the FPS system, power
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This note was uploaded on 04/25/2009 for the course 222 AND 34 dynamics a taught by Professor Ibrahim during the Spring '09 term at American University of Sharjah.

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LN_Sec_14-4_one - POWER AND EFFICIENCY (Section 14.4)...

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