EXAM 1 CH 1 Smart Rocks are considered for ballistic missile defense One watt is equivalent to one calorie second The asteroid that killed the dinosaurs exploded because It got very hot from the impact Kinetic energy can be measured in calories Which of the following statements is true Power is energy divided by time Power or Energy Horsepower P kilo watt hour E watt P calorie E Hybrid vehicles run on electric power and gasoline What is the main reason that hydrogen driven automobiles have not replaced gasoline ones Hydrogen is too difficult to store in automobiles Compared to an equal weight gasoline U 235 can deliver energy that is greater by a factor of One Million Which of the following contains the most energy per gram Uranium Compare the energy in a kilogram of gasoline to that in a kilogram of flashlight batteries the gasoline has about 400 times as much energy Which is least expensive for the same energy delivered Coal The kinetic energy of a typical 1 gram meteor is approximately equal to the energy of 150 grams of TNT Coal reserves in the United States are expected to last for hundred of years A limitation for all electric automobiles is Low energy density per battery Solar power is about 1 kW per square meter The efficiency of inexpensive solar cells is closest to 12 A human running up stairs can briefly use power of approximately 1 horsepower A 12 oz can of soft drink not diet or lite contains about 150 Calories A large nuclear power plant delivers energy of about 1 gigawatt Electricity from a AA battery costs 1000 per kilowatt hour Electricity fro wall plug costs 10c per kilowatt hour The energy per gallon not pound of liquid hydrogen compared to gasoline is about 3x less Most of the hydrogen we use in the US comes from it is manufactured from fossil fuels or water You have 10 tungsten bulbs and each uses 100 watts You leave them all on for an hour The energy used is 1 kilowatt hour The kinetic energy of a bullet per gram is within a factor of 2 none of the above CH 2 If you double the energy content of a kilogram of gas the temperate of the gas measured on the absolute K scale doubles About how fast are molecules in air moving 1000 ft s Temperature is the measure of average kinetic energy In a bucket of water the instantaneous speed of the molecules is closest to approximately 1000 ft s A refrigerate operating in a room warms the room Molecular motion stops at 0 K Water melts at 0 C A gas heater warms a room mostly through convection A table has the same temperature as the air above it That means the molecules in the air and in the table have the same average velocity The velocity of sound increases when the temperature increases If a gasoline engine produces a hotter explosion then the efficiency of the engine should goes up A cup full of water made of plastic feels warmer than one made of glass because plastic conducts heat better than glass The atom with the fewest number of protons is hydrogen How many atoms are there if you move across a human hair About 125 000 The speed of sound is approximately 1000 feet per second Put hot glass in cool water It shatters because the outer surface of the glass contracts rapidly but the inner part doesn t Sea level is rising from global warming The main cause is expanding sea water The temperature warms by 2 C That is approximately the same as 4F To heat a room using the least energy do it by using natural gas to run a heat pump There is almost no hydrogen gas in the atmosphere because it escapes the earth s gravity At Mach 10 if all the energy of a meteorite went into heating it its temperature would be about 30 000 C The New Orleans levees failed because they were weaker at the thermal expansion joints If the temperature rises by 5 C 9 F then the rise in sea level will be about 4 feet For a typical auto the fraction of the gasoline energy wasted as heat is about careful this may be a trick question 80 Temperature in the sun is not defined well When material is cooled some things contract and some expand The melting temperature of object is usual equal to its freezing point Absolute zero is the temperature of nothing When a liquid boils the increase in volume liquid to gas is typically a factor of 1000 If the temperature of a gas in a container goes from 0 C to 300 C the pressure will become 300 times greater Firewalking is similar to water on a saucepan For gasoline to explode it requires to be mixed with oxygen To be more efficient the temperature difference between the ignited hot fuel and the cool part of the engine should be as large as possible Heat flow through empty space no atoms present occurs through radiation Entropy optional topic measures disorder Molecular motion stops at 0 K CH 4 Energy from the Sun is produced primarily by fusion The mass of the nucleus is closest to 99 of the entire atom Radioactivity in the Earth leads to all of the above energy for volcanoes helium for toy balloons heat for geysers LD50 refers to lethal does A major reason your body is radioactive is that you eat radioactive carbon in your food The primary cause of death from the Hiroshima bomb was the blast from the bomb Fission fragments are among the most dangerous kinds of radiation Wine made from fossil fuels is not radioactive because the radioactivity has decayed away If the half life of an element is big that means that it decays slower that one with a small half life Muller wears a wristwatch with tritium in the watch hands because After three half lives the fraction of nuclei remaining is 1 8 Most of the elements found on earth were created within a star The fraction of the U S populations that dies from cancer is typically about 1 in 5 Watch dials containing radium glow because the radium hits a phosphor Choose all the items that derive from radioactivity helium for balloons volcanic lava warmth in deep mines After four half lives the surviving tritium atoms are removed Compared to completely new tritium atoms they are expected to live exactly as long One rem of radiation does takes how many gammas per square about 2 000 000 000 Which requires the larger does CANCER The linear hypothesis is widely used even though it is not proven A sievert is how many rem 100 Cancer is lower in Denver because We don t know why The number of deaths from the Chernobyl accident is about 24 000 Radioactivity is used in smoke detectors The source of energy in the Sun is fusion of hydrogen Which of the following is most toxic per gram Botox The
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