A machine which has an efficiency of 80% raises a load of 50N through a vertical height of 10m. The work input to the machine is:
Correct answer: D. 625 J
- A. 400 J
- B. 500 J
- C. 800 J
- D. 625 J
Explanation
%efficency=(output work/input work)*100 input work =(output work/%efficency)*100output work=Fd=50*10=500 putting values in the above formula; =( 500/80)*100 =625 joule
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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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