Moderate
If you weigh 500 N and in 5 seconds you can run up a flight of stairs consisting of 40 steps, each 15 cm high, what is your power?
Correct answer: B. 600 watt
- A. 3000 J
- B. 600 watt
- C. 3000 J sec-1
- D. 60 kilowatt
Explanation
h (15)(40) cm = 600 cm = 6m W = mg = 500N P= mgh/t => (500)(6)/5 => 600 watt
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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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