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

Bernoullis equation, Bernoulli's equation In an irrotational fluid, to...

Bernoulli's equation In an irrotational fluid, total of the static pressure, the weight of the fluid per unit mass times the height, & half the density times the velocity squa

Ray diagram, how to make a ray diagram ?? and what are f, p ?? and what is ...

how to make a ray diagram ?? and what are f, p ?? and what is refraction index?????

What is nucleus, What is nucleus?               It is the type of an ato...

What is nucleus?               It is the type of an atom where whole mass of the atom is supposes to be concentrated. Or it is the central part of an atom which have proton and

What is the meaning of polarization, What is the meaning of Polarization? ...

What is the meaning of Polarization? Polarization is a quality that is only exhibited by transverse waves. For light waves, the polarization identifies the direction of vibrati

Malus law, state and explain malus law?

state and explain malus law?

Differences in construction of MOSFET and JFET, Differences in Construction...

Differences in Construction of MOSFET and JFET An N-channel JFET is demonstrated in figure (a). It comprises a thin N-type silicon bar with two islands of P-type semiconductor

what is the formula of temperature gradient?, The  temp gradient  is s...

The  temp gradient  is similar to finding the slope of a line (when in two dimensions) Temp. Gradient= Change in Temp. value/Distance. dT/dx = (T2 - T1)/(X2 - X1)

Different semiconductor materials: germanium, (1)          Melting point...

(1)          Melting point : 936 0 C (2)          Atomic number : 32 (3)          Energy gap : 0.6ev (4)          It is a gray metallic looking mat

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