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

Claculate deviation, A ray of light is incident normally on an equilateral ...

A ray of light is incident normally on an equilateral prism of refractive index 3/2 calculate devition. Ans) since the prism is equilateral therefore angle of prism is 60 0 =

Decade resistor, DECADE resistors are wire wound resistors. These are wound...

DECADE resistors are wire wound resistors. These are wound on cards moulded on round a switch of low contact resistance. Alloys used for wire are Manganin, minalpha, etc. Bifilar w

Describe dispersive power, Write down the expression for deviation produced...

Write down the expression for deviation produced by a thin prism also describe dispersive power.

Describe how the law of conservation of energy, Describe how the law of con...

Describe how the law of conservation of energy holds good in light interference pattern

What is the basic difference between current and voltage, They are exactly ...

They are exactly analogous to water pressure and water flow by a hose. That's why flowing electrons is known as a current, just like a water current. Voltage is the electromotiv

What is tyndal scattering, Q What is Tyndal scattering? Tyndal scatter...

Q What is Tyndal scattering? Tyndal scattering- When light passes throughout a colloidal solution its path is visible inside the solution. This is for the reason that the

Who first american physicist win two nobel prizes, What is the name of the ...

What is the name of the first American physicist to win two Nobel prizes? Ans: (John) bardeen was the first American physicist who win two Nobel prizes.

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