A strain gauge, having a gauge factor of 2, is mounted on a rectangular steel bar (E = 200. 10°KN/m”). The bar is 3 cm wide and 1 cm high and is subjected a tensile force of 30 kN. Determine the resistance change of
the strain gauge if the resistance of the gauge was 120 2 in the absence of the axial load.
Solution
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Apiston-cylinder with a volume of 0.25 m3 holds 1 kg of air (r 0.287 k/kgk) at a temperature of 100 c. heat transfer to the cylinder causes an isothermal expansion of the piston until the volume triples. how much heat is added to the piston-cylinder?

Two flowing streams of argon gas are adiabatically mixed to form a single flow/stream. one stream is 1.5 kg/s at 400 kpa and 200 c while the second stream is 2kg/s at 500 kpa and 100 ? . it is stated that the exit state of the mixed single flow of argon gas is 150 c and 300 kpa. assuming there is no work output or input during the mixing process, does this process violate either the first or the second law or both? explain and state all your assumptions.

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