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Question 7 The beam AB supports a uniformly distributed load of 2 kN/m and two concentration load P and Q. It has been experimentally determined that the normal stress due to bending in the bottom edge of the beam is -56.9 MPa at A and -29.9 MPa at C. Draw the shear and bending moment diagrams for the beam and determine the magnitudes of P and Q P 18 mm 2 kN/m 36 mm A 0.1 m 0.1 m 0.125 m Ans: Vmax = 1150 N; Mmax=221 Nm; P=500 N, Q=250 N Question 7 A timber beam is loaded and supported as shown below. At section A-A of the beam, determine the flexural and shearing and stresses on horizontal planes that pass through points a, b, and c of the cross section. 10 KN a b 50 mm 50 mm 100 mm B 150 mm 1 m 2 m Ans: a=0 MPa, b=187.5 kPa, c=250 kPa Question 8 The beam shown in fig below is composed of three pieces of timber that are glued together as shown in below. Determine a) The maximum horizontal shearing stress in the glued joints. b) The maximum horizontal shearing stress in the wood. c) The maximum tensile and compressive flexural stresses in the beam. 100 mm 6 kN 6 kN 50 mm 9 kN.m B 140 mm 50 mm 2.0 m *0.5 m (a) (b) Ans: (a) 371 kPa (b) 563 kPa (c) ±10.94 MPa 0.5 m* B Glued joints