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

Conservation of energy, CONSERVATION OF ENERGY 1.   Potential energy ...

CONSERVATION OF ENERGY 1.   Potential energy is, as the word suggests, the energy "locked up" up somewhere and which can perform work. Potential energy Potential energy can b

Schrodinger''s time independent wave equation: free particle , Q.   Write d...

Q.   Write down the Schrodinger's time independent wave equation for a free particle confined in one dimensional box of size a. Obtain eigen values and normalized wave functions fo

Displacement and velocity, an object moves from postion +16m to the postion...

an object moves from postion +16m to the postion +47m in 12s.what is its total displacement and its average velocity?

Find total equivalent internal resistances of the batteries, For the circui...

For the circuits shown in Figure the resistors show the internal resistance of the batteries. Find, in each case: (i) The total e.m.f. across PQ (ii) The total equivalent in

Torque and equilibrium, What is the effect of torque and equilibrium on tap...

What is the effect of torque and equilibrium on taps,doors,handlebars and bicycles?

Explain interference of waves, Interference of waves: When two waves of...

Interference of waves: When two waves of similar amplitude and period traveling in the similar medium superpose, they reinforce each other at one point and cancel at others. Th

Atomic Physics, Assignment Just question and answer Quotation; how much

Assignment Just question and answer Quotation; how much

What are the stars, What are The Stars? The star is made of dust and ga...

What are The Stars? The star is made of dust and gas in space. Essentially it has many stages they are 1.black hole 2.nuetron star 3.supernova 4.red giant stage

Basics of conducting materials, what is the difference between cohesive ene...

what is the difference between cohesive energy and binding eneergy

What are intrinsic and extrinsic semiconductors, What are intrinsic and ext...

What are intrinsic and extrinsic semiconductors? A semiconductor is a material that has an electrical conductivity among that of a conductor and an insulator. In a semiconducto

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