Class 2 Notes

# Class 2 Notes - PROBLEM 2.9 Two control rods are attached...

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Unformatted text preview: PROBLEM 2.9 Two control rods are attached at A to lever AB. Using trigonometry and ‘ F“ knowing that the force in the right-hand rod is F2 = 20 lb, determine “——f (a) the required force F l in the left-hand rod if the resultant R of the forces exerted by the rods on the lever is to be vertical, (b) the corresponding magnitude of R. SOLUTION Using the Law of Sines i _ R _ 201b sina sm38° sinﬁ 0‘ = 90° - 10° = 80°,ﬁ = 180° — 80° — 38° = 62° Then: Fl _ R _ 201b sin80° sin38° sin62° . or (a) Fl = 22.3 lb 4 (b) ,R = 13.951b 4 PROBLEM 2.18 For the hook support of Prob. 2.7, determine, using trigonometry, the magnitude and direction of the resultant of the two forces applied to the support knowing that P = 500 N and a = 60°. SOLUTION Using the triangle rule and the Law of Cosines, Have: 6 = 180° — 45° 6 = 135° Then: R2 = (900 N)2 + (500 N)2 — 2(900 N)(500 N) cos135° or R = 1302.46 N Using the Law of Sines, 500 kN _ 1302.46 N siny sin135° or y = 15.7056° and [3 = 60° + 15.7056° [a = 75.751° R = 1.302 kN 4: 758° { PROBLEM 2.23 Determine the x and y components of each of the forces shown. 7 250mm t 110 mm 7 SOLUTION A \ \ I. 3, Determine the following distances: QSON I / ago N dOA = ,/(—160 mm)2 + (300 mm)2 = 340 mm 0 (a '0 N dOB = (600 mm)2 + (250 mm)2 = 650 mm \‘c. doc: (600mm)2+(—110mm)2 =610mm 680 N Force: P; = 680 NM 340 mm P; = —320 N 4 300 Fy = 680 N( m) lTllTl Fy = 600 N 4 390 N Force: 5; = 390 NM 650 mm P; = 360 N 4 F = 390 N (250 m) y 0 mm Fy = 150 N 4 610 N Force: P; = 610 NM 610 mm P; = 600 N 4 —110 Fy = 610 N( m) 10 mm F.=—110N< PROBLEM 2.34 Determine the resultant of the three forces of Prob. 2.23. T Problem 2.23: Determine the x and y components of each of the forces mm shown 110 lnm _f SOLUTION From Problem 2.23: FDA = —(320 N)i + (600 N) j FOB = (360 N)i + (150 N)j FOG = (600 N)i — (110 N)j R = 2F = (640 N)i + (640 N)j R = (640 N)2 + (640 N)2 = 905.097 N 640N 640N tana= a = 45.0° R=905 N A: 45.0° { ...
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## This note was uploaded on 10/05/2009 for the course CE statics taught by Professor Epstein during the Spring '09 term at UConn.

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Class 2 Notes - PROBLEM 2.9 Two control rods are attached...

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