The power of a pump which can pump 100 kg of water to a height of 100 m in 5 sec is:
Correct answer: A. 20 kW
- A. 20 kW
- B. 200 kW
- C. 40 kW
- D. 4 kW
Explanation
To calculate the power of a pump, you can use the formula for power: Power (P) = Work Done (W) / Time (t) In this case, the work done is equal to the potential energy gained by lifting the water to a height of 100 meters. The potential energy (PE) is given by the formula: PE = m * g * h Where: m is the mass of the water (100 kg) g is the acceleration due to gravity (approximately 9.81 m/s²) h is the height (100 m) Now, let's calculate the potential energy: PE = 100 kg * 9.81 m/s² * 100 m = 98100 J (joules) Next, we'll use the formula for power: Power (P) = Work Done (W) / Time (t) Given that the work done is 98100 J and the time is 5 seconds: P = 98100 J / 5 s = 19620 W Now, let's convert this to kilowatts (KW) by dividing by 1000: P = 19620 W / 1000 = 19.62 KW So, the power of the pump is approximately 19.62 KW.which is closest to option A) 20 KW, but it's slightly lower due to rounding in the calculations. Therefore, option A) 20 KW is the best choice.
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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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