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

Explain the total magnetic flux in the ring, A coil of 600 turns is wound u...

A coil of 600 turns is wound uniformly on a ring of non-magnetic material. The ring has a uniform cross-sectional area of 200mm 2 and a mean circumference of 500mm. If the current

What is the difference between unit cell and primitive cell, What is the di...

What is the difference between unit cell and primitive cell In primitive cell, number of atoms per unit cell is one while if number of atoms per unit cell is greater than one i

Photodissociation, is there any way to photodissociate explosives or bullet...

is there any way to photodissociate explosives or bullet so that it can not fired

Radio communication , Production of sound messages by a microphone in a rad...

Production of sound messages by a microphone in a radio station (studio). 1) Audio frequency generation. 2) Generation of r.f. carrier wave. 3) Modulation in a transmitter, b) 4

Momentum, A bullet with mass m is fired into a block of a mass M intially a...

A bullet with mass m is fired into a block of a mass M intially at rest at the edge of a frictionless table of a given height. the bullet remains in the block, and after the impact

Determine two-wattmeter method of measurement, (a) Show that the total powe...

(a) Show that the total power in a 3-phase, 3-wire system using the two-wattmeter method of measurement is given by the sum of the wattmeter readings. Draw a connection diagram.

Briefly explain working of michelsons interferometer, Q. Briefly explain wo...

Q. Briefly explain working of Michelsons Interferometer? Michelson designed an instrument for the measurement of wavelength of sodium light, thickness of thin film and for many

Measurement, How do we measure the height of a house

How do we measure the height of a house

Combination of resistors in parallel, Regard as three resistors having thre...

Regard as three resistors having three unique values of resistance. Presume the resistors are connected in parallel with each other. Additional suppose that the parallel combinatio

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