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

Define heat engine, Define Heat engine Heat engine is a device by which...

Define Heat engine Heat engine is a device by which a system is made to undergo a cyclic process that results in conversion of heat into work. It is explained as the ratio o

Magnetic lines of flux, Magnetic lines of flux   A line of flux is ...

Magnetic lines of flux   A line of flux is a line indicating the direction in which a free north pole would travel, if placed in the field at that point. Alternatively it

Motion in one dimension, a ball is dropped from a bridge 122.5m high. afte...

a ball is dropped from a bridge 122.5m high. after the ball has been falling for2 sec another is thrown straight downwards after it. the initial velocity of the ball is such that

Magnetomotive, A)   Wirte two materials that are magnetic and two that are ...

A)   Wirte two materials that are magnetic and two that are non-magnetic? B)  Explain magnetic induction C)  Describe what is meant by "Magnetomotive" force?

Define phase, Phase (Φ) : The amount which express at any instant, the disp...

Phase (Φ) : The amount which express at any instant, the displacement of the particle and it's direction of motion is known as the phase of the particle. If two elements of the

How much energy does the atom lose, An electron in a hydrogen atom makes a ...

An electron in a hydrogen atom makes a transition from E 3 to E 1 . How much energy does the atom lose?

Heat loss in a cylinder, different combination of pipe material, insulation...

different combination of pipe material, insulation material and it size.

A see-saw lever, A see-saw lever Get a thick plank about 3 m long and b...

A see-saw lever Get a thick plank about 3 m long and bring it into the class room. Balance it over a box or some other suitable device and let the pupils experiment with the se

State the applications of JFET, State the Applications of JFET FET is u...

State the Applications of JFET FET is used as a (1)  Buffer amplifier (2)  Low Noise Amplifier (3)  Cascaded Amplifier (4)  Analog Switch (5)  Chopper (6)  Ph

Energy conservation on an incline, Energy Conservation on an Incline In...

Energy Conservation on an Incline In the given case of the cart rolling down predispose and there are three external forces (the general force, the force of friction and air re

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