On a day that the temperature is 6.0°C, a concrete walk is poured in such a way that the ends of the walk are unable to move. Take Young's modulus for concrete to be 7.00 × 109 N/m² and the compressive strength to be 2.00 x 109 N/m². (The coefficient of linear expansion of concrete is 1.2 × 10-5 (°C-¹).) (a) What is the stress in the cement on a hot day of 49.0°C? N/m² (b) Does the concrete fracture? ○ Yes ○ No

9-90. The starter for an electric motor is a full cylinder and has the cross-sectional areas shown. If copper wiring has a density of Peu = 8.90 Mg/m³ and the steel frame has a density of Pst = 7.80 Mg/m³, estimate the total mass of the starter. Neglect the size of the copper wire. Problem 9-90 Steel Copper 80 mm 50 mm 30 mm 100 mm 60 mm

A copper wire has a length of 4.5 m and a diameter of 3.6 mm. under what load will it's length increase by 0.30mm?

The figure below shows the connection of a cylinder head to a pressure vessel using 12 bolts of ISO grade 5.8 (SP = 380 MPa, SY = 520 MPa, E = 207 GPa). The cylinder diameter is 100 mm. The bolts used are M 12 x 1.75 with At = 84.3 mm2 and the bolt grip is 40 mm. The flanges (members) are both made of steel having stiffness parameters (A = 0.78715, B = 0.62873, E = 207 GPa). If the internal pressure in the cylinder is 10 MPa, determine: a) The torque required to tighten the bolts for reusable connection. b) The bolt and members’ stiffnesses and the joint constant. c) The resultant load in each bolt d) The maximum and minimum stresses in each bolt. e) Is the connection safe?