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

Nicol prism, applications of nicol prism?

applications of nicol prism?

Find capacitance, For a parallel-plate capacitor with plate area "A" and pl...

For a parallel-plate capacitor with plate area "A" and plate separation "d", the capacitance is proportional to which of the following? a) A divided by d squared b) A tim

What are the properties of surface tension, There are six properties of sur...

There are six properties of surface tension:- Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Special Relativity, What would happen if the principle of relativity is pro...

What would happen if the principle of relativity is proved wrong?

The original frequency of the tunning fork, A tunning fork produces 4 beats...

A tunning fork produces 4 beats per second with another tunning fork of frequency 256 Hz. The first one is now loaded with a little wax and the beat frequency is found to enhance t

Angular frequency of the resulting shm, A sphere of mass m and radius r is ...

A sphere of mass m and radius r is on a smooth fixed inclined plane in equilibrium, if now the sphere is displaced by a small distance along the plane , what will be angular freque

Calculate power required to operate the fan, A centrifugal fan is used to p...

A centrifugal fan is used to pump air. The fan rotor is 1 ft in diameter, and the blade spacing is 2 in. The air enters with no angular momentum and exits radially with respect to

Electronics, define capacitor filter briefly?

define capacitor filter briefly?

Explain mirror - lens equation, Q. Explain Mirror - Lens Equation? A ce...

Q. Explain Mirror - Lens Equation? A central equation in optics relates the focal length, object distance and image distance for a thin lens or mirror. This equation is general

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