Two uninsulated, rigid tanks contain air. initially, tank a holds 0.45 kg of air at 800 k and tank b has 0.9 kg of air at 500 k. the initial pressure in each tank is 345 kpa. a valve in the line connecting the two tanks is opened and the contents are allowed to mix. eventually, the contents of the tanks come to equilibrium at the temperature of the surroundings, 289 k. assuming the ideal gas model, determine the amount of energy transfer by heat, in kj, and the final pressure, in kpa.

Afoot bridge is made as a simple deck, 4 m long, with a cross section 2 m (wide) and 20 cm thick, and made of wood. the deck is supported at the two ends. the maximum load allowable on the bridge is 10 tons, provided it is uniformly distributed on the deck. to sense this load, a strain gauge is placed at the center of the bridge and its resistance is monitored. if the sensor has a nominal resistance of 350 s2 and a gauge factor of 3.6, what is the reading of the strain gauge at maximum load? the modulus of elasticity for the wood used in the construction is 10 gpa.