6. A nickel-steel rod at 21 C is 0.62406 m in length. Raising the temperature to 31C produces an elongation of 121.6 uam. The coefficient of linear expansion is 7. The specific heat of many solids at very low temperatures varies with absolute temperature T according to the relation c=AT, where A is a constant. The heat energy needed to raise the temperature of a mass m of such a substance from T=0 to T=20K is 8. Which type of ideal gas will have the largest value for Cp-Cv? (a)Monatomic (b) Diatomic (c)Polyatomic (d) The value will be the same for all 9. Which of the following states can not express the second law of thermodynamics? (a) You can not change completely heat energy into work (b)The entropy of an irreversible process never decreases (c) You can not transfer heat energy from a low-temperature reservoir to a higher temperature reservoir without doing work (d)The entropy of a closed system never decreases Il. An observer is standing on a platform of length 65 m. a train passes at a relative speed of 0. 80c moving parallel to the edge of the platform. The observer S notes that the front and back of the train simultaneously line up with the ends of the platform at a particular instant. (12) (a)According to S, what is the time necessary for the train to pass a particular point on the train? (b)What is the rest length of the train? (c)According to an observer S on the train, what is the length of the platform? Ill. The force of interaction between two atoms in certain diatomic molecules can be represented by F=-ar+b/r in which a and b are positive constants and r is the separation distance of the atoms. Then(a)find the separation at equilibrium; (b) for small oscillations about this equilibrium separation,write out the equation of the motion(Hint: expand the force at equilibrium separation and do the first order approximation) and find the solution for the equation;(c) find the period of the motion.(122 6. A nickel-steel rod at C D 21 is 0.62406 m in length. Raising the temperature to C D 31 produces an elongation of 121.6 μm. The coefficient of linear expansion is __________________. 7. The specific heat of many solids at very low temperatures varies with absolute temperature T according to the relation c=AT3 , where A is a constant. The heat energy needed to raise the temperature of a mass m of such a substance from T=0 to T=20K is ________________________. 8. Which type of ideal gas will have the largest value for Cp – Cv ?_________________________ (a) Monatomic (b) Diatomic (c) Polyatomic (d) The value will be the same for all. 9. Which of the following states can not express the second law of thermodynamics?___________ (a) You can not change completely heat energy into work. (b) The entropy of an irreversible process never decreases. (c) You can not transfer heat energy from a low-temperature reservoir to a higher temperature reservoir without doing work.. (d) The entropy of a closed system never decreases. II. An observer is standing on a platform of length 65 m. A train passes at a relative speed of 0.80c moving parallel to the edge of the platform. The observer s notes that the front and back of the train simultaneously line up with the ends of the platform at a particular instant. (12’) (a) According to s, what is the time necessary for the train to pass a particular point on the train? (b) What is the rest length of the train? (c) According to an observer s’ on the train, what is the length of the platform? III. The force of interaction between two atoms in certain diatomic molecules can be represented by F= -a/r2 +b/r3 in which a and b are positive constants and r is the separation distance of the atoms. Then (a) find the separation at equilibrium; (b) for small oscillations about this equilibrium separation, write out the equation of the motion (Hint: expand the force at equilibrium separation and do the first order approximation) and find the solution for the equation; (c) find the period of the motion. (12’)