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

Beats, Is beats, which we study in physic similar as we consider beats of s...

Is beats, which we study in physic similar as we consider beats of sounds like bass. bits

Explain start-up current in the bulb, The cold filament resistance of a lig...

The cold filament resistance of a light bulb is 20.0). The bulb consumes 75 W when it is operating from a 120-V source. By what factor does the start-up current in the bulb

What is a wave front?, A locus formed by joining the points which are at th...

A locus formed by joining the points which are at the equal distance from the source....is called wavefront...

Rayleigh-jeans law, Rayleigh-Jeans law For any blackbody at thermodyna...

Rayleigh-Jeans law For any blackbody at thermodynamic temperature T, the radiancy R onto a range of frequencies among nu & nu + dnu is provided by R = 2 pi nu 2 k T/c 2 .

Show the biasing of a light emitting diode, With the help of a diagram, sho...

With the help of a diagram, show the biasing of a light emitting diode (LED). Give its two benefits over conventional incandescent lamps.

Vernier caliper, Write the expetiment of vernier caliper?

Write the expetiment of vernier caliper?

Experiment of a simple gears, Simple gears With a hammer and a medium-s...

Simple gears With a hammer and a medium-sized nail, make holes in the exact centres of various used bottle caps. Straighten the edges of the caps to make them as round as possi

Seeing your whole body in a flat mirror, Is it possible to see your whole b...

Is it possible to see your whole body in a flat, planar mirror that is LESS THAN half your height if the mirror is at an angle? (i.e. not parallel to your body)

Factors affecting induced emf, FACTORS AFFECTING INDUCED EMF By experim...

FACTORS AFFECTING INDUCED EMF By experiment, the following factors may be noted: • The faster the magnet (or coil) is moved, the greater is the deflection obtained on the meter

Quantum particle confined to one dimensional box, A quantum particle confin...

A quantum particle confined to one dimensional box of width 'a' is in its first exited state. What is the probability of finding the particle over an interval of (a/2) marked symme

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