On a day that the temperature is 20. 0"�, a concrete walk is poured in such a way that the ends of the walk are unable to move. Take Young’s modulus for concrete to be 7.00 × 102 �/m2 and the compressive strength to be 2.00x109 N/m2 . (a) What is the stress in the cement on a hot day of 50. 0"�? (b) Does the concrete fracture? (4%)

Not all tiles will be usedidentify the element present in each star based on the gaps observed in wavelengths of its light refer to this table containing absorption wavelengths (in nm) of several different elements the table ishelium 447, 502 ,587 ,668carbon 427 ,515, 600 ,678sulfur 425, 565, 639, 675xenon 484, 590, 687calcium 429 ,527, 593, 645silver 421 ,521, 662

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.