Power is transferred through a machine as shown. What is the efficiency of the machine?
Correct answer: A. Po / Po+ PL
- A. Po / Po+ PL
- B. PL / Po
- C. PL/ Pi
- D. Po / Pi
Explanation
Power transferred through a machine; input power = Pi ; output power =PO ; Power loss=PL . From the law of conservation of energy Pi =PO +PL . Efficiency of a machine= useful output power / input power= Po/Pi; substitute Pi =PO +PL ; we get η= (Po / Po +PL)
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About Work and Energy
Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
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