The pin-connected structure consists of a rigid bar abc, a solid bronze [e = 102 gpa, 14.3 × 10−6/°c] rod (1), and a solid aluminum alloy [e = 61 gpa, 23.6 × 10−6/°c] rod (2). bronze rod (1) has a diameter of 25 and aluminum rod (2) has a diameter of 16 mm. the bars are unstressed when the structure is assembled at 32°c. after assembly, the temperature of rod (2) is decreased by 40°c, while the temperature of rod (1) remains constant at 32°c. assume l1 = 290 mm, l2 = 490 mm, a = 210 mm, and b = 410 mm. determine the normal stresses , in both rods for this condition (positive if tensile, negative if compressive).

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Air inially occupying a volume of 1 m2 at 100 kpa, 27 c undergoes three internally reversible processes in series. process 1-2 compression to 500 kpa during which pv constant process 2-3 adiabatic expanslon to 100 kpa process 3-1: constant-pressure expansion to 100 kpa (a) calculate the change of entropy for each of the three processes. (b) calculate the heat and work involved in each process. (c) is this cycle a power cycle or refrigeration cycle?

When subject to a steady load (within elastic range) over a long period of time, what is the major difference in material behavoir between steel and plastic?