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

What is dielectric constant, When a dielectric field is completely full in ...

When a dielectric field is completely full in among charges rearrangement of the charges inside the dielectric medium takes place and the force among the same tow charge reduces by

Transformation of kinetic energy to potential energy, Q. Transformation of ...

Q. Transformation of kinetic energy to potential energy? A tiny ball at the end of string is swung in a circular vertical loop. The speed of rotation is reducing to the point t

Zeroth law of thermodynamics, Zeroth law of thermodynamics If two bod...

Zeroth law of thermodynamics If two bodies are each in thermal equilibrium along a third body, then all of the three bodies are in thermal equilibrium along with each other.

Are there different type of slide emitting fibers, Are there different type...

Are there different type of slide emitting fibers? Nowadays some types of side emitting fibers are marketed. Several most common given as follows: Solid core optics

Cause of difference in length of day and night, Demonstrating the cause of ...

Demonstrating the cause of difference in length of day and night in some places:- Use the similar apparatus as in 6 above. Mark a circle on the ball around its centre to show t

Explain impulse, IMPULSE: When a force acts on a body for a very short ...

IMPULSE: When a force acts on a body for a very short time, the product of the force and the time for which the force acts, is called the impulse or impulse of force".

Illustrate huygens principle, State and illustrate Huygens' principle. Expl...

State and illustrate Huygens' principle. Explain the consequences of total internal reflection.

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