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

Experiment of measuring jar or graduate, A measuring jar or graduate Se...

A measuring jar or graduate Select several straight-sided glasses jars of assorted sizes. Olive bottles are very useful for the making of graduated cylinders. Paste a strip of

Rectilinear motion, An elevator is stopped at the ground floor. It starts m...

An elevator is stopped at the ground floor. It starts moving upwards at constant acceleration a>0 for 5 seconds. It then keeps a constant speed for 35 seconds. Finally, it slows do

Spectrum, Show that the spectrum of thermal radiation for T ¼ 300K peaks at...

Show that the spectrum of thermal radiation for T ¼ 300K peaks at approximately 10 microns Minimum 100 words accepted

What is the concept of time, Q. According to classical mechanics, what is t...

Q. According to classical mechanics, what is the concept of time ? As-per to classical mechanics (i) The time interval among two events has the same value for all observers

Making a jam jar aquarium, Making a jam jar aquarium If a large glass t...

Making a jam jar aquarium If a large glass tank is not available, practically any glass vessel can be used as a easy aquarium if it is well stocked with submerged water plants

Explain transistor, Transistor: An active semi-conductor device with th...

Transistor: An active semi-conductor device with three terminals that is emitter base and collector is known as transistor. Types of Transistor: There are two types of

Determine the voltage resolution of converter, 1. A 12-bit analog-to-digita...

1. A 12-bit analog-to-digital converter (ADC) works over the range of -5 volts to + 5 volts.  (a) What is the voltage resolution of this converter?   (b) Assuming -5 V is rep

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