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# Яблонский. Решение задач (решебник) / ТерМех Яблонский - Решения задач (1-15 вар) / 14_var / С-2 вар 14 / С-2 вар 14 / С2_14

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 2 ( 14) http://www.termeh.ru

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: P1 = 3 , P2 = 5 , P3 = 5 , = 3 , α = 60 .

 .1 1. RA RB . RA ! X A A . M A (Fi ) = 0; - 1 × a ×tg60 - 2 × 2a - 3 ×3a + RB × 4a = 0 i R = 0.25 P1 + 0.5P2 + 0.75P3 = 0.25 ×3 + 0.5×5 + 0.75×5 » 7.549 . 3 3 Fix = 0; 1 - X A = 0 X A = 1 = 3 . i Fi = 0; A - 2 - 3 + RB = 0 A = P2 + P3 - RB = 5 + 5 - 7.549 » 2.451 . i " RA = X A2 + A2 = 32 + 2.4512 » 8.874 . 2. ( . .1). Ð = 30 , = 2 , = # 3 . 3a # tgÐ B = Ð B = 30 , Ð B = 60 . 3a EL = DEL, . ", ÐL = ÐLD = 30 , ÐDL = ÐBL = 60 , BL = DL. \$ BL = DL, BL = KL, . . DL = KL, ÐDLK = 180 - ÐDLE - ÐBLE = 180 - 60 - 60 = 60 , , % DKL , 60 . # DK ÐD K = 30 ; ÐBKD = 60 ; BD = 2a; DK = BD ×tgÐBKD = 2a ×tg60 = 2 3 a = 2 a. 3 3 # DCK tgÐDCK = DK = 2 3a = 2 a CD 3 cos ÐDCK = 1 = 3 ; sin ÐDCK = tgÐDCK ×cos ÐDCK = 2 × 3 = 2 . 1+ (2 7 3)2 7 3 7
 http://www.termeh.ru 3. ( . .1) & : - N1 sin 60 = 0 N1 = = 2.451 » 2.830 ; sin 60 0.5 3 N2 - N1 cos 60 - X A = 0 N2 = X A + N1 cos 60 = 3 + 2.830 ×0.5 = 4.415 . &B: RB - N12 sin 30 = 0 N12 = RB = 7.549 » 15.098 ; sin 30 0.5 N12 cos30 - N13 = 0 N13 = N12 cos30 = 15.098×0.5 » 13.075 . 3 & : N13 - N10 = 0 N10 = N13 » 13.075 ; N11 - P3 = 0 N11 = P3 = 5 . & : P + N cos60 - N sin 60 = 0 N = P1 + N1 cos 60 = 3 + 2.830 ×0.5 » 5.098 ; sin 60 1 1 4 4 0.5 3 N1 sin 60 + N4 cos 60 - N3 = 0 N3 = N1 sin 60 + N4 cos 60 = 2.830 ×0.5 + 5.098×0.5 » 5 . 3 & : N3 - N5 sin ÐKCD = 0 N5 = N3 = 5 » 6.614 ; sin ÐKCD 7 2 N6 - N2 - N5 cos ÐKCD = 0 N6 = N2 + N5 cos ÐKCD = 4.415 + 6.614 × 3 » 8.745 . 7 &D: N - N cos30 - N = 0 N = N10 − N6 = 13.075 − 8 .745 » 5 . cos30 10 9 6 9 0.5 3 N7 - P2 - N9 sin 30 = 0 N7 = P2 + N9 sin 30 = 5 + 5×0.5 » 7.5 ; &L: N8 cos30 + N9 cos30 - N12 cos30 = 0 N8 = N12 - N9 = 15.098 - 5 » 10.098 ; " & ' " DE N1 = 2.830 – EL N2 = 4.415 + EH N3 = 5 + DH N4 = 5.098 – AD N5 = 6.614 – HL N6 = 8.745 + AH N7 = 7.5 + CL N8 = 10.098 – KL N9 = 5 – HK N10 = 13.075 CK N11 = 5 + BC N12 = 15.098 – BK N13 = 13.075 + : N5 = 6.614 , N6 = 8.745 , N8 = 10.098 .