A pump raises 100 kg of water through 10 m in 20 seconds. Taking g as 10 m per second squared, its power output is
Correct answer: A. 500 W
- A. 500 W
- B. 1000 W
- C. 200 W
- D. 10000 W
Explanation
The work done is mgh, that is 100 multiplied by 10 multiplied by 10, giving 10,000 J, and dividing by 20 seconds gives 500 W. Forgetting to divide by the time leaves the 10,000 distractor, which is the energy rather than the power. The pump's input power would be higher than this, since no machine is fully efficient.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Power
Power is the rate at which work is done or energy is transferred, with average power calculated over a time interval and instantaneous power found from P = Fv when force and velocity are aligned. Work includes units, mechanical efficiency, and the distinction between power and total work or energy.
Practise Work and Energy
748 free Work and Energy MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.