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

Describe magnetic susceptibility, It is the property of the substance which...

It is the property of the substance which defines how easily a substance  can be magnetized. It may also be defined as the ratio of intensity of magnetization (I) in a substance to

Define the intensity of the laser in short, Define the Intensity of the las...

Define the Intensity of the laser in short. Intensity: a. Lasers are intense and bright light sources. It is due to coherence and directionality. b. The  intensity  is  e

Kinetic energy and potential energy, Assumptions: Kinetic Energy=KE, Potent...

Assumptions: Kinetic Energy=KE, Potential Energy=PE m=mass of the skateboarder=55 kg, Velocity v=1.80m/s So ,Initial Energy(KE) of the skateboarder=mv 2 /2 = 0.5* 55 * (1.8)^

What are polar molecules, What are polar molecules Polar molecules - mo...

What are polar molecules Polar molecules - molecules having of two or more atoms that are neutral but have a charge which is not distributed uniformly.

A simple model of the earth and moon, A simple model of the earth and moon ...

A simple model of the earth and moon The earth can be shown by an orange or other round object stuck on a piece of bamboo or a meat skewer. A piece of bent wire or knitting nee

What is the path of the infinitesimal magnetic field, Points O, A, and P li...

Points O, A, and P lie in one as well as the same vertical plane. Point A is 4 . 0 cm due east of point O starting at point O one is able to arrive at point P by going 6 . 0 cm due

What are the units of fibre optic communication system, What are the units ...

What are the units of fibre optic communication system? Fibre Optic Communication System: This comprises of the given three most important units: a. Transmitter: It has i

Explain the planets, Explain The planets? The planets:- We know in the ...

Explain The planets? The planets:- We know in the solar system that the sun is set and that moving round it are a number of large spheres called as planets . These are nine pla

Heat therapy - c- radiowave heating( diathermy), C- Radiowave Heating( Diat...

C- Radiowave Heating( Diathermy) Short wave diathermy utilized electromagnetic wave in radio range ( ~10m ) and microwave range (~ 12cm) .Short wave diathermy penetrate deep into

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