12_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

# 12_Mechanics SolutionInstructors_Sol.Manual-Mechanics_Materials_7e.book_Gere_light.1

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Unformatted text preview: 01Ch01.qxd 6 9/25/08 7:49 PM Page 6 CHAPTER 1 Tension, Compression, and Shear Problem 1.2-6 A car weighing 130 kN when fully loaded is pulled slowly up a steep inclined track by a steel cable (see figure). The cable has an effective cross-sectional area of 490 mm2, and the angle a of the incline is 30°. Calculate the tensile stress st in the cable. Solution 1.2-6 Car on inclined track FREE-BODY DIAGRAM OF CAR TENSILE STRESS IN THE CABLE W Weight of car T Tensile force in cable Angle of incline A R1, R2 Effective area of cable Wheel reactions (no friction force between wheels and rails) st T A Wsin a A SUBSTITUTE NUMERICAL VALUES: W A st 130 kN 30° 2 490 mm (130 kN)(sin 30°) 490 mm2 133 MPa ; EQUILIBRIUM IN THE INCLINED DIRECTION © FT T 0 Q+b T W sin a 0 W sin Problem 1.2-7 Two steel wires support a moveable overhead camera weighing W 25 lb (see figure) used for close-up viewing of field action at sporting events. At some instant, wire 1 20° to the horizontal and wire 2 is at an angle is at on angle 48°. Both wires have a diameter of 30 mils. (Wire diameters are often expressed in mils; one mil equals 0.001 in.) Determine the tensile stresses 1 and 2 in the two wires. T2 T1 b a W ...
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## This note was uploaded on 12/22/2011 for the course MEEG 310 taught by Professor Staff during the Fall '11 term at University of Delaware.

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