Power, Physics

Assignment Help:

Power:

The rate of doing work is called power, and it is defined as the work done in unit time.  As a formula, this would be:

power = work done/time Taken

 Power is expressed in several different units, such as the watt, ergs per second, and foot-pounds per second.  The most common unit of power in general use in the United States is the horsepower.  One horsepower (hp) is equal to 550 ft-lb's or 33000 ft-1b/min.  In the metric system the unit of power is the watt (W) or the kilowatt (kW).  One hp is equal to 746 watts; and 1 kW = 1.34 hp.

Example:

To compute the power necessary to raise an elevator containing 10 persons a distance of 100 ft in 5 s (assuming the loaded elevator weighs 2500 lb), proceed as follows:

Power = work done/Time Taken        = 2500 x 100/5                 = 50,000 ft-lb's/sec

 

    Since 1hp = 550 ft-lb's/sec then required hp = 50,000/550

      = 90.9 hp (67.81 kw assuming no friction losses)

 

 


Related Discussions:- Power

Luxon, luxon: A particle which solely travels at c (the speed of light...

luxon: A particle which solely travels at c (the speed of light in vacuum). All of the luxons have a rest mass of zero exactly. Though they are massless, luxons carry momentum

Show the conditions for total internal reflection, Show the conditions for ...

Show the conditions for total internal reflection to happen. Arrive at the relation between refractive index and critical angle. What do you mean by optical fibre? on what rules do

Doppler effect wave fronts, Doppler Effect: Wave Fronts Describing the...

Doppler Effect: Wave Fronts Describing the wave fronts of a wave for a moving source. The Doppler effect is a phenomenon experiential whenever the source of waves is moving al

Motion of satellite, assignment on the above topic in minimum 15 pages

assignment on the above topic in minimum 15 pages

Temperature, If the temperature in a room is 84 degrees at the floor what w...

If the temperature in a room is 84 degrees at the floor what will it be at a 30 foot ceiling

Illustrates some applications of holography, Illustrates some applications ...

Illustrates some applications of holography? Applications of Holography Holography can be put to many of uses other than recording images. Holographic data storage is a proc

Who discovered proton, Who discovered Proton? In 1886 Eugen Goldstein d...

Who discovered Proton? In 1886 Eugen Goldstein discovered canal rays (also called as anode rays) and showed that they were positively charged particles (ions) formed from gases

Comparison between System and Control Volume , Thermodynamics, Similarities...

Thermodynamics, Similarities between System and Control Volume (a) System and Control Volume are defined by careful in description of their boundaries. (b) System and Control Vol

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd