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

Newto, why electron move in orbit

why electron move in orbit

How much pressure produced by cylinder, How much pressure produced by 6" di...

How much pressure produced by 6" diameter cylinder with height of 14" at 95 degrees Celsius

Write about isaac newton, Write a short (approx. one page) review of the co...

Write a short (approx. one page) review of the contribution of one of the following people to the historical development of Physics;   Aristotle Ibn al-Haytham Ga

Determine the voltage drop across each impedance, The following three imped...

The following three impedances are connected in series across a 40V, 20kHz supply: (i) a resistance of 8, (ii) a coil of inductance 130µHand5 resistance, and (iii) a 10 r

Evaluate the path of the magnetic field, A straight vertical wire passes by...

A straight vertical wire passes by a wooden table top. The wire carries an upward directed current. Evaluate the path of the magnetic field of the wire at a point on the table top

Assignment, composition of simple harmonic motion

composition of simple harmonic motion

Explain reverse bias, Reverse Bias: When P-types material of a semi con...

Reverse Bias: When P-types material of a semi conductor diode is linked a negative potential and the n-type material is linked at positive potential of a voltage source, the di

Suidqs (super conducting quantum interference devices), SQUIDs, or super co...

SQUIDs, or super conducting Quantum interference devices are used to measure minute changes in magnetic flux by means of a pair of Josephson junctions, often used to detect extrem

Resistance measurements, Resistance measurements: An example of how to ...

Resistance measurements: An example of how to make AC voltage measurements is shown in the diagram below. Once again, the red and black test leads are connected to the '+' and

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