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

Electric potential , As we know that"The electric potential at a certain po...

As we know that"The electric potential at a certain point inside the electric field is defined as the amount of work done in bringing a unit positive test charge uniformly (without

Explain radiate energy, An aluminum rod at a temperature of 100 o Celsius ...

An aluminum rod at a temperature of 100 o Celsius radiates energy at a rate of 10 watts. If its temperature is enhanced to 200 o Celsius, at approximately what rate will it radia

Specific latent heat, explain specific latent heat of fusion with formula

explain specific latent heat of fusion with formula

Heat engines.., which one of the following engine has thr highest effecienc...

which one of the following engine has thr highest effeciency carnot engine or rankine engine or otto engine?

What do you mean by mobility, Q Define: mobility. Give its unit. The mo...

Q Define: mobility. Give its unit. The mobility is defined as the drift velocity obtains per unit electric field. The unit of a mobility m 2 V 1s 1.

The proton and neutron are collectively called, The proton and neutron are ...

The proton and neutron are collectively called as: (1) Deutron (2) Positron (3) Meson (4) Nucleon Ans: (4) Nucleon

What is the meaning of rate constant in the rate expression, A reaction is ...

A reaction is first order in A and second order in B. (a) Write differential rate equation. (b) How is the rate affected if the concentration of B is tripled? (c) How is

Fsdfasdf, #questidfasdfasdfasdfasdfon..

#questidfasdfasdfasdfasdfon..

Evaluate the uniform speed of gondola, Evaluate  the uniform speed of gond...

Evaluate  the uniform speed of gondola? Q. The world's largest ferris wheel with a radius of 50.0 m is located in Yokohama City, Japan. Each of the sixty gondolas on the wheel t

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