Monday, 23 December 2019

What is Power, definition Formula, Units, equation-Physics

  Daman       Monday, 23 December 2019
Hello friends, We are discussing about What is Power, formula equation and its units. Start thinking like physics scientist. Have you ever noticed that if a person A climb up the 10 stairs within 5 seconds, Another person B who is quite active than the earlier one,  climb up the same number of stairs (which is actually 10)  into 2 seconds Which has more Power. Now question is in your side which one you found more powerful? 

Definitely,  a person who is active enough or we can say a person B. More Power with less time.

Now here are definition of power starts.
Define Power :The amount of work done in number of seconds is known as power.
Its formula is p is equals to force divided /time. The equation for power is

P= W/t

Formula of Power

  • Now learn, p is reciprocal(inversely proportion) of t time. Now, one can easily predict that if lessen time is taken by an object to do work it means that it it has more power. Keeping force constant.
P=(inversely proportion)1/time
  • Similarly, if an object is taking more number of seconds it means an object is doing his work with less p. keeping force constant.
  • It can be easily noticed that power is directly proportional to force. It implies that more energy is required to do  a work of higher power than that of less power. Keeping time constant

            P=(directly proportion)Work

Things should be remember

  • The Units for Power is Watt , j/s.

  • The unit of work is joule, may be higher values like kj.
  • Unit of time is in seconds. It may be minutes and hours depending upon the type of question the examiners has given to you.
What is Power, definition Formula, Units, equation-Physics

Power Physics Formula 

Another things to keep in mind,

We can change the formula of power  in physics by placing work with its formula Force x distance. 

W=Force x S(distance)

If you look carefully, then it becomes p is equals to to force x distance divided by time 
P=(F x S)/t

Looking more consciously, one can easily find the distance upon time is equals to speed. But the work is done in particular direction. 

So, we can say that it's not a speed, it's a velocity with particular displacement. Now the formula becomes p is equals to F  x V . The power is equal to

P=F(Force) x V(velocity)

We can use this formula to calculate power and for sorting out various numericals which we find tough enough.

Below are the numericals which helps you to give a view of attempting numericals given by your teacher. Take a look

  • If a huge force acts on an object, but the displacement of the object is zero then what can we say about the work done and power?
Work done on the body is defined as the force applied on the body producing a net displacement on the body. Work Done = Force × Displacement. If the application of force produces no displacement the work done on the body is zero.  Hence, P =Zero.

  • A man of mass 50 Kg runs up a flight of stairs having a rise of 5m, is 4s. a) What is the work done by the man? b) What is the average power developed by the man?
 Power = Work Done(P.E=mgh)/ Time Taken
              =  625 W.


Thanks for reading What is Power, definition Formula, Units, equation-Physics

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