8.4 - 8H pr/l(flT/MS J To Big/slag I 50 SHEETS 22-142 100...

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Unformatted text preview: 8H pr/l(flT/MS J To Big/slag I 50 SHEETS 22-142 100 SHEETS 22-144 200 SHEETS 22441 Hzéfly Nara g." Col/(a. [as was dc.” 09/9/0670] //7 #56, /’75 am/ gag/m7 777/6 [flab/(ms mew The, dfl/w/y fix/Z74. ~ baf ma Na/ pa Wer &” I/éVsdTI/ITj 0'? (Mafia came, w/fl) /1/2w~t7*0/)'s [ippflkflflMS To Phys/(3.. [WC/Mic 2 WWK lema = Force. a Distance, A/OTZ Forco mus-f [06 parallel 7‘0 MOT/CV) (In The: 0r oppamra d1 maria/JD, [Um/Ts ] [ Fara; War/Q mfernaflor’w gnawmomt); me‘farc‘m) ? douch (J) § (31;) on 1+3 M a“ I ‘ \m g _B":Iv'rl$h:’nff8 ‘ PW’Y’m’b); 71‘ +095) 75001" pound Goff/5) [Convwstfiii 1 Ho 2» 4.45. fit, .1 «(at = O. 305 m. -1 H410 c /. 36 j. vJC/er CQ'OVW, on 600 Calculcfié Obdecj' Mm a farce, 0? 21b. moves‘w 39-6; w : a up % 3+2: :2 Q; Lia—Ila. 22-141 50 SHEETS 22442 100 SHEETS 22-144 200 SHEETS / W?“ I ..VfiL‘i_A/gyaflfvazwns it? h 1% yéIC s This Is 791:: “foml work dome m movmg 7%”) X=—0L_ +0 xcb when flame, 5 a 7%) FIX) 0F Posmm X. a when Com/OMSS/ng (L Spmng) HOG/{(33 Lmo scu/s {Ema ’13 proporriom/ 7‘5 dlsf'ance So F (x): K x. How much wark "IS done, in COM/DMSS a slap/n3 CL dzsmme 013- 0.3m whera K = 8 nae/m? 0.5 73%.;wa f Bxc/x (Wales) EQUihbrlU'M a 8. Li 4p p.MflbflflhL.£b¥éK§ I _ _ , r3 T5 50 SHEE 22-141 n 224/32 TOUSHEETS [.7 22.1.44 2m SHEETS \ /~\ /rw~ / m ‘ ’U"!!‘l\ "\L Mags vs. Wei h+ mass 22 gummy 0F marf’fer in (m dyad way/mt 2: @rce exefied 53 yravzg or) (Dr) 0/3607“ ( d1FF€r€n+ or) ear‘r‘hgfimoa N <2 w +00% and Law- F = m 3 Aescmbes Hm downward graVHaTt-omj 1%rre/ acwrg on (L. magsmq. / c} 2: 0/.8 I’m/$2- % a; :33 {Lt/57' K6. pom} when Hm. wag)th 07‘: an ObjéC‘f ")3 9/va dam mul‘fip/y b3 3 #29 gefffla grawmfloiw 7%rre, ~— ba+ I~P~ any #6, W33 ‘23 git/en) you may Geno/Me, my. “pound” ‘13 a WM 0? we};th (Bm'Sén'rsr ('kal‘yvam” Is a umT 0*? W638 ('0) U 'newfon” 1.3 a unn‘ 01° u;th ’t 1 new+on = 4K9 » m/S‘1 L, QM Applmumiim*fhyéms i , \ 271 1 5:) SHEET§ 33) 22442 1.09 SHEETS / 2 V4 ZDOSHEFTS \n M rm \ //\ 1/ I???» To NH cm owed up) 30M am oppos‘mj Tm 1%rca OF ymwg wifi’) an egual fart?) bow m ‘fhe, opposirc direcfion ,. How much work '13 done “FT/QC) a a pound book 3 936+ 0104* 7%: fiber .7 W : .pcme/ 99 d LS’fCU’lCC’, :, a a— 3 [Ed How much Work is done, [WTng (L 1K3. boOK l Meier 011F- flwe, Hanoi? W =- cha *— (Ats’Fance 2» mg * i m = (,1 k9) (W mkl) (4 m3 :2- (31.8 jet/U63: recall: ankle, : neerone me'fer newfon = 1 K3 0 mlsi’j ETS .ETS ‘ : SHE m ‘ \ 22—141 22-142 1cm SHEETS ff . . . Mrm n/ wiaiijzpilcarlo/ls Physics Example (5 firm P3335; % Example6 Solution It is reported that the Great Pyramid of Egypt was built in 20 years. If the stone making up the pyramid has density 200 pounds per cubic foot, find the total amount of work done in building the pyramid. The pyramid is 410 feet high and has a square base 755 feet by 755 feet. Estimate how many workers were needed to build the pyramid. Volume of slice m 32Ah 755 it Figure 8.49: Pyramid for Example 6 We assume that the stones were originally located at the approximate height of the construction site. Imagine the pyramid built in layers as we did in Example 5 on page 349. By similar triangles, the layer at height It has a side length 3 = %(410 —— h) ft. (See Fig- ure 8.49.) The layer at height It has a volume of 32 Ah ft3, so its weight is 20032 Ah lb. This layer is lifted through a height of h, so Work to lift layer = (20052 Ah lb)(h ft) = 200.92}; All ft — lb. Summing over all layers gives 755 2 Total work e Z 20032 hAh = Z 200 (410 — h)2h Ah ft-lb. Since h varies from 0 to 410, as Ah ——> 0, we obtain 410 755 2 Total work 2/ 200 (410 ~ h)2h dh % 1.6 - 1012 foot-pounds. 0 We have calculated the total work done in building the pyramid; now we want to estimate the total number of workers needed. Let’s assume every laborer worked 10 hours a day, 300 days a year, for 20 years. Assume that a typical worker lifted ten 50 pound blocks a distance of 4 feet every hour, thus performing 2000 foot-pounds of work per hour (this is a very rough estimate). Then each laborer performed ( 10)( 300) ( 20) (2000) = 1.2~108 foot-pounds of work over a twenty year period. Thus, the number of workers needed was about (1.6 - 1012)/(1.2 ‘ 108), or about 13,000. 4 '82:} )9 ,1le canoflsLj'zLflfifhychS ,, V 4: p. 22-142 100 SHEET: 50 SHEETS 22—144 200 SHEETS 22441 ’\ fl NIDAD/ \\ / // ( F0 me; (Q @733 u Y8» * Can (Ase our T€Chmé2U€3 To .707th €><er+ed on a surface: 0 Examples Include fiwe/ 010 H20 an "Hm: 777617710 (See Ex?))7§ 373) Or on ‘ Hm Homer Dam (see, 8.8) 10957179, 6 Pressure, Increases LUMLI’) gig/97% 3 § Pmssmm :— weg‘mi- + ale/97% 2 W3“ gnu/I73 v14 Gig/975 g a For a cons+an+ pregame Over'ck 3AM) area)» Force, —‘ Presgure, v’F Heck 7 3H flpfllLaaTIQ/zs __Pby5/Z‘$ , l [7 50 SHEETS 190 224M, 200 SHEETS \ 22-191 227142 \, \\l§ N"! P ’\ t:‘/ r\ much work 'Is mammal To II€+ a, [mo-kg sm‘fi/h’ré To an air/hide, 0F aw/aém above We sarfice 0F Hm), QaVHO ? The gmvammnal farce is F = W whey/<2 A Q) at 1,?- 0‘ \f; I o E ["Z. M = mass of earth m .: mags 010 safelllfi Y‘ : pits-fame [Deween +hem 'Tha. menus 010 ecmLh is (0.4409 m) 1+3 mass Is (9910“ K93 and m they: ( _. n -11 Uni—f3, Hm gmwfanoml Cons-ram E7 = 61(470/0 gain g‘qsmc ‘Tc‘Tcd work 7— JF 0h? @4406 .4 '0‘; i 3.446"; : fflfl {r : (‘,€“Mm>) ‘ w r ‘ M, b.4406 6-4 L) 5 SHEET$ SHEETS 1m 22-141 W M“; 22—142 \ 22-144 ZOGSHEETS /’\ / “ \Afl: . Afifipphcaflamswjiamfhyflcsm A Csam) H 1000410. wegmr ~Is bang IIF+€J +0 a, her/o‘th 0‘9 IO 1066+ 09F +ha flround. 1+ 13 i1:!ij 03mg (z V‘O/OC’, which Magi/)5 1% //9. per find/t é Lama?) '13 being pailaf’ up by ECO mflruamn workers s+andujzf7 on 4. mm" :50 15%., fine ground. Find fine work done To /1P+ five, way/47L. Sch”) 1 x i ‘z a fl UH wenthr cm may? heifihn“ Ah of»! 2 “H16 ground.) «EC» Rom (A begin-f OF A) W6 I mus+ cQo work on boflv) Hue wagmt plus, 1 The amoun+ 01“ rope 00+ ge+ pulled 0N0 mafl ‘o Swim Woo? 3647+ (109.j Hwereis 30-h ’51:, 010 rope remammg o-F rope“ ._. _. go magi/1+ 09 HMS b)?” 013 mpg, (Bo-H}? a warm To “5+ WWW Plus rope U10 Ah ;—_—> [1000 + 4(2:o-~h)3 Ah « __ - v 3) “ I— “ dw’tancc ( ()rc; ’ IS , "way/NJ ‘10 ‘ T0er NUYK 1‘ f [1000+ li(30'h)16“’) c) H3 000 “9‘ ...
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8.4 - 8H pr/l(flT/MS J To Big/slag I 50 SHEETS 22-142 100...

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