A150-kg copper block initially at 85°c is dropped into an insulated tank which contains 75 l of water (use  =1000 kg/m3 ) at 30°c. determine the final equilibrium temperature and the total entropy change for this process. since you do not know the final temperature, use specific heats evaluated at 300k as a first approximation. answers: 38.57 °c, 0.7056 kj/k.

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.