A mass of 20 kg is lifted from the floor to a height of 2m in 4.9 sec. Calculate the power in Watts:
Correct answer: B. 80 W
- A. 60 W
- B. 80 W
- C. 100 W
- D. 120 W
Explanation
The formula for calculating power, P is:P=mgh/tWhere m is the mass, g is the gravitational acceleration, h is the height and t is the time.∵ P=(20)(9.8)(2)/4.9Solve the equation to obtain:P=80W
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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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