A. We choose the heat capacities of aluminum, silver, gold, tungsten and 70Cu-30Zn brass at constant pressure, at room consumption.

B. Compare the details of these values, highlight the difference, explain . Determine which of the following pairs of materials will have the higher thermal conductivity. Specify the operations for the selection to be made.

a. pure copper; Aluminum bronze (95% Cu-5%Al by mass)

b. molten silicon dioxide; quartz

c. Linear polyethylene; branched polyethylene

D. Randomly sliced (polyestrene-butadiene) co-polymer; variable(polystyrene-butadiene) co-polymer A cylindrical rod with a length of 250 mm and a diameter of 6.4 mm is placed between two rigid supports. When this bar, which does not contain any stress at room temperature (20 oC), is cooled to -40 oC, a maximum thermal tensile stress of 125 MPa occurs in the bar. For this to happen, which of aluminum, copper, brass, 1025 steel and tungsten, metal or alloys should be used in the manufacture of the bar? From where?

a) Determine the type and magnitude of stress that will develop in the bar when a 0.5 m long 1025 steel bar, fixed at both ends and fixed at both ends, is heated from 20 oC to 80 oC. b) What is the magnitude of the stress in the bar at 20 oC? c) If this bar in part (a) is cooled from 20 oC to -10V, determine the type and magnitude of the stress. I5. What measures can be taken to reduce the possibility of thermal shock of a ceramic part. Explain by giving examples.