Power
Power
Power :Power can be defined as the amount of work done per unit time.
Some examples :
1. You may have noticed that old people find it difficult to climb a flight of stairs quickly. But they can easily climb the same flight of stairs slowly. In both cases they spend the same amount of their stored energy and do the same amount of work in climbing the stairs. But the rate at which energy is spent or work is done is different in the cases.
2. Let us take another example. You can keep your hands immersed in lukewarm water for hours. But you cannot keep them in boiling water the cases. However, the rate at which energy is transferred is different in the two cases. As a result, they have different effects.
We see that in many cases the rate at which work is done or energy is transferred is an important quantity. Hence, this quantity is given a separate name - power. The rate at which work is done by a force is called the power delivered by that force.` Also, the rate at which energy is transferred by an object (like a machine) is called the power delivered by that object.
Definition :
The time rate of doing work is defined as power(P) . If equal works are done in different times, power will be different. More quickly work is done, power will be more.
As work W is measured in joules and time t in seconds, the unit of power is joule/second. This unit is given a separate name - watt. If work is done at the rate of 1 joule per second, the power P delivered is 1 watt (1 watt = 1 joule/second). The symbol of watt is W. Kilowatt (kW) and megawatt (MW) are also commonly used units of power.
Another common unit of power is the horse power. Horse power is written in short as hp. Horse power is related to watt as
1 horse power = 746 watt
A person of mass 75 kg climbs up a 30 step staircase in 10 seconds. If the height of each step is 10 cm, what was his power? | |||
| Right Option : B | |||
| View Explanation | |||
If a boy weghing 450 N climbs up a rope through a height of 1m in 1s, what is the power exerted by him? | |||
| Right Option : A | |||
| View Explanation | |||
A man A of mass 80 kg runs up a staircase in 12 seconds. Another man B of mass 80 kg runs the same staircase in 11 seconds.The ratio of powers of A and B is | |||
| Right Option : C | |||
| View Explanation | |||
Students / Parents Reviews [20]
I have spent a wonderful time in Abhyas academy. It has made my reasoning more apt, English more stronger and Maths an interesting subject for me. It has given me a habbit of self studying
Yatharthi Sharma
10thBeing a parent, I saw my daughter improvement in her studies by seeing a good result in all day to day compititive exam TMO, NSO, IEO etc and as well as studies. I have got a fruitful result from my daughter.
Prisha Gupta
8thMy experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
Ayan Ghosh
8thWhen I have not joined Abhyas Academy, my skills of solving maths problems were not clear. But, after joining it, my skills have been developed and my concepts of science and SST are very well. I also came to know about other subjects such as vedic maths and reasoning.
Sharandeep Singh
7thThird consective year,my ward is in Abhyas with nice experience of admin and transport support.Educational standard of the institute recumbent at satisfactory level. One thing would live to bring in notice that last year study books was distributed after half of the session was over,though study ...
Ayan Ghosh
8thIt was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
Eshan Arora
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Yogansh Nyasi
7thAbhyas institute is one of the best coaching institute in the vicinity of Ambala Cantt area. The teachers of the institute are well experienced and very helpful in solving the problems of the students.The good thing of the institute is that it is providing extra classes for the students who are w...
Aman Kumar Shrivastava
10thThe experience was nice. I studied here for three years and saw a tremendous change in myself. I started liking subjects like English and SST which earlier I ran from. Extra knowledge gave me confidence to overcome competitive exams. One of the best institutes for secondary education.
Aman Kumar Shrivastava
10thAbhyas institute is one of the best coaching institute in the vicinity of Ambala cantt.The institute provides good and quality education to the students.The teachers are well experienced and are very helpful in solving the problems. The major advantages of the institute is extra classes for weak...
Shreya Shrivastava
8thWe started with lot of hope that Abhyas will help in better understnding of complex topics of highers classes. we are not disappointed with the progress our child has made after attending Abhyas. Though need to mention that we expected a lot more. On a scale of 1-10, we would give may be 7.
Manya
8thMy experience with Abhyas academy is very good. I did not think that my every subject coming here will be so strong. The main thing is that the online tests had made me learn here more things.
Hiya Gupta
8thIn terms of methodology I want to say that institute provides expert guidence and results oriented monitering supplements by requsite study material along with regular tests which help the students to improve their education skills.The techniques of providing education helps the students to asses...
Aman Kumar Shrivastava
10thIt was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
Cheshta
10thMy experience with Abhyas academy is very nice or it can be said wonderful. I have been studying here from seven class. I have been completing my journey of three years. I am tinking that I should join Abhyas Academy in tenth class as I am seeing much improvement in Maths and English
Hridey Preet
9thA marvelous experience with Abhyas. I am glad to share that my ward has achieved more than enough at the Ambala ABHYAS centre. Years have passed on and more and more he has gained. May the centre flourish and develop day by day by the grace of God.
Archit Segal
7thAbhyas is good institution and a innovative institute also. It is a good platform of beginners.Due to Abhyas,he has got knoweledge about reasoning and confidence.My son has improved his vocabulary because of Abhyas.Teacher have very friendly atmosphere also.
Manish Kumar
10thAbout Abhyas metholodology the teachers are very nice and hardworking toward students.The Centre Head Mrs Anu Sethi is also a brilliant teacher.Abhyas has taught me how to overcome problems and has always taken my doubts and suppoeted me.
Shreya Shrivastava
8thAbhyas Methodology is very good. It is based on according to student and each child manages accordingly to its properly. Methodology has improved the abilities of students to shine them in future.
Manish Kumar
10thMy experience with Abhyas Academy has been very good. When I was not in Abhyas whenever teacher ask questions I could not speak it confidently but when I came in Abhyas, my speaking skills developed and now I am the first one to give the answer of teachers question.
