Power

Power

 

                 Power is the rate of work done or rate of energy consumed. We can manually pedal a wheel of bicycle at 1 revolution per second. If we want to turn the same wheel with 10 revolutions per second, we need more power and will use engine. 

Power is the time rate of doing work (or expending energy).

P    =       W/t      

      =       Fd/t   

      =      mgh/t

The SI power unit is called watt (W) in honor of James Watt (1736-1819), a Scottish engineer who developed one of the first practical steam engines. A common unit of electrical power is the kilowatt (kW). Power tells you how fast work is being done or how fast energy is transferred.

The SI unit for power is watt. 
One watt is equal to 1 Newton-meter per second (Nm/s). 

If you were pushing on something with a force of 1 N, and it moved at a speed of 1 m/s, your power requirement would be 1 watt. 

British unit of power is horsepower.

The conversion is as follows: SI:

  Watts (W) 1000 W = 1 kW Kilowatt (kW) 
                      1kW = 1.341 hp Horsepower (hp)
                      1 hp = 0.746 kW