Answer Happy

9. The water flowing out of the physics department faucet has a speed of 20 m/s. What is the height of the water in the water tower that is supplying water to this faucet? (Neglect any friction.) a) 20 m b) 6.4 m c) 20,000 m d) 14 m e) None of the above. 10. A car with a tire radius of .300 m drives a linear distance of 300.0 m while decelerating uniformly. How many revolutions does the tire experience while coming to rest? a) 1000 revolutions b) 90 revolutions c) 159 revolutions d) 500 revolutions e) None of the above. 11. Which of the following best describes the 1st law of thermodynamics? a) Absolute zero temperature can never be reached. b) If two objects are held at the same temperature, then they are in thermodynamic equilibrium with each other. c) A heat engine cannot extract heat energy from a hot source (or reservoir) without discharging some heat to a cold source (or reservoir). d) It is a re-statement of the conservation of energy. 12. A modern nuclear power plant can produce energy at a rate of 2 GW. If all of this power was used to warm up an Olympic-sized swimming pool with a mass of 2x10 kg. how long would it take to warm up the pool by 30°C? Round the answer to three significant figures. (C-1 cal/g°C. 4.19 J-1 cal, pwater = 1,000 kg/m³) a) 3,610 sec b) 30,500 sec c) 15.4 sec d) 30.9 sec e) 126 sec f) None of the above