Govt. of West Basal HEAT AND WORK uw seleotion of the vatue of « to suit cach particalar vase, With forced draught and « high rate of combustion d may be ué low as 60, and the, ‘rave incronscs as the drauglt und rate of vanbustion diarnich, "AN tho values of « given ubave ure for touporalires om the’ Fabrenheit scaly and Q in B-Th U. For temperatures on tho Conti. Bago rale wg i CLT, ihe ave naan a mt beanie Profouor Oshorne Reynolds, in a paper rend before the Manchester Literary and Philosophies! Soviety in 1874, first called attention, 26 in nese a ie! iy of Mh id oar the wun the na on the rete of heat wanomission and. wiygrsted the formbla BD A's Bo, where is the anonnt of haat branerntted per degree dlificonce of tamperature of Suid and sustel,« isthe velooty of flow ff the duid over the surtace, p is the densty uf the Maid, and A and R are constants, ‘De, J.P, Nicholaon hax veloped the. Oslghge Leynelas formula sud ine given the blowing guaced trmuiat MY too Leonean heat froma a ges Rowing along Aloe. = [Sor eatse af B.TLLU. teaorivitted per syuare font of tue surface per bour, ‘eimperature of gs flowing aloug the flue in deyives Fab. temperature of metal wall uf ue iu degrows Fab, dy) = mien gun fw temnporntare in degroon Fab. ‘ontity of gaa i Th. per ouio foot. ett velocity of qu in feet por second, weigh of gus flowing yer second in Th. ares ofgigo iu square iuches. periindM of flue in inches, nus o/em hydraulic mean depth of flue or tube, ‘The fallowing extanple worked out by Ve. Nicholson will serve to lintirate the application of his forule, ‘Lancashire boiler fue, 2k inches diameter. Ceul Uprnt on u grate 207 aquare fect aros, 100'Ih, per hour. Air 21 1b. por/ pound of ooal. Temporetuce of gases Inaving Se, 2200" ¥. ‘Temparatre of gases ab drop fine, 900° Vo Sten temperature, 350° F. 200+ 900 i) ‘The avernge value of @y = 180-4 380 = Ot ametal ia equal to the tomparatare of the ste, 990, susuming that the temperature of che ve atateseh 22 80 %23 per ett a8, wn OX 2 yy wrqusiode wo aos, samioroa in nto baile “Fon Fain of Cael caseey HEAT ENGINES 2x36 36 1x56, ‘Therefore Q (fe visit m= 9 inches, ta. + 5092 x 1200 6100 BARU. por aquare foot per hou. 45, Work.— When force acting on & body oauses that body to innve, the foree is snid to do wark. Also, if a body ix moved against » resistames, work is done in overcoming the resistancs, ‘Tho amount of ‘work done dopends on the magnitude uf the foree anc also on the “distance through whieh it acts. Tn muewsnring work the unit which ig gaueenlly used by engineers is ‘the work done when a forus of tus pound acts trough a distence of ‘oue foot, this unit boing called a feat-pownd, If the unit teken bo tho work dono when w Kuve of auc ton acts dhrough a distauee of ome foob, ft fs ealled a footsiow, ‘Pho foot-ton ia used in measuring large qsatition ot work, Hor minating small quantition of work the tichprnud, oF ‘the work dina when a force of ame pound sole Hooagh x dntance of cane inch, is frequently used. Tho work done Ky a force is found by multiplying the magaftude of the torco by tho distance throug’ which it acts. 16, Turning Moment-~Work fm Turning.—When a force T acting on a body causes that body tw rointe about a Bxud axis, the Hine of notion of the force being in w plane perpoudienlar to that ax, the product of J', the nughitude of the force, and the yerpend divteneo It uf its line uf action from the mais is ealled the teraing moment or torgue of the driving forue 1. VP is ta pouyds and ti in foot, the turning motaont PH is in puted-fect or fortrpownde ; hut it 2 ik in pounds and ix in inekes, PR is Si pound inches ov fach-pounds, the ling of action af 1 is not in a plano porpendicaar tw tho axis of rotation, but mmukew un angle @ with that plang then the turning x t11 04] t550~ 36 moment is Pit sd, TER, the luforago of P, romnine coustant during the rottion of the body, and if the magnitude of P is also oonstont, then if u is the angle J radians fheoagh which the body tue the distance rough whieh P acts fs uli, and the work done by P is Pol, or To, where T is the turning mowent, If the leverage R or the foro T, or both, shusld vary, then if T is the mean ‘urning moment the work done in Tis. Te the amount of turning is sivon as » revolutions, then the distance through which P ucts is alta, and the work done is aVRa, or eT. 1% Rate of Work—Hores-power—The working power, of aay agent depends on the émount of work which it ean do in u given time, ‘Watt found that a good working borse sould do 33,000 font-pounds of work in one tninnts, aud he introdaced this us the unit for measuring ths working power of steum enginn. A searm-ongine or any working agent is maid ty be of one horse-prncer when it eando 33,000 foot-pomnds ‘work in one minuto, or 550 foot-pounds ia one second. vidunty the simplo cule for Sing the horsepower of soy work, ng agent, oF the horse-power transmitted by any piovo of machinery, is UEAT AND WoRK 19 to divide the number of foot-pounds of work done or trensmitted ininate ty 39,000, or horsepower equals work per mscond. divided by Bi, TTorse-power is « mesewe of the rafe of doing or transmitting vork. T horsepower per hour or 1 horne-pomer-hour = 39,000 x 60 foot- pounds per hour, 18. Bleotrical Units and their Mechanical Equivalents The leetmmiotive force, or lactic pressure of an elovtrio current, in scusurad ii voles, and the atrength of the eurrent, or the rate of floor ‘if tho cleolvicity scrum a seotion of the conductor, ie mensured empires, Tho prove of a eaereat of I empire at ah elvetrieal pressure o€ L volt in onfled a eatt, Wolls % niupired = watts, 1 horse-power 746 watts, 1 kilowatt = 1000 watts — 3405 bon power 44,836 footpounda per winute. | cloetsicul unit or | Board of ‘edo unit = 1000 watt-lnta, . 19. Hnergp.-.fn mechnics the torn energy weans enpacity for doing work pee Potentind Kaergy is energy duo w the relntive position of one body to another, or of one pact af a lily U another part, when the two Dbedlios or tha part of the sano body are under thn setion of » foros or forees tending to aller {hate relative positions. For example, n body which ia ullowou to fall towards the uareh teny be nade tr do work’; Thooes befor 16 bogins to fall it possesses potential energy. or energy duc t ils position iu relation to the earth. A. onmpressed spiral sp Inns potential onurgy, becuse if it ia allowed to resume its unstrained forut ig ou he mass to do work, —Likewine eranpremed air possesses pitontinl energy. ‘Tha caargy stored inn ples of cel ie putoatal eaergy, and wader favourable conditions the uloas of the constituents of tho eral and the ntoni of the oxygen of the uir will rush together and produce boat which may bn converted imo work. Kinetia Energy in enorgy don to the niotion uf a body. A gallon of water at reat at a height of 100 feet above the Jevel ot the see. joareasos 1000 ftolb. of ptentinE energy, and if this water is allowed to fall frvaly to tha lovol of tha wea, without doing work om tbe way, it will in very position af itt fall postore 1000 fib, of anergy, but as i6 oaconds ite potential energy will diminish, aul the remainder of the 1000 fab, well bo ntotual i the water as kinetic energy. When the gallon of water ha fallon 25 fout, ite potential energy will be reduccd 4 750 ftTb, and ite Kinotio energy will then be 290 fb, Tf o body of weight W 1b. fulle frucly fram reeb through a height of & feet it will then bave stored in it We (t.lb. of kinetio energy, and. ita velocity #iMl then be, » = 4/3 fest per sound. Henvo tho kinetic cong Wh sul Ton on ns ini my body weighing W lb,, andaoving with a velocity of » foot por seonnd, ‘will bo the same, nomaely, ye whatovar be the enuse of the velocity, wer, for exeimple, the cause be the forea of gravity, aa in falling ody, oF the forve of an oxplogion, aa ia a gus,