Physics 1020 Exam 1 Study Guide Chapter 1 Energy Terms Power is the rate of energy release Energy is the ability to do work A Calorie is the amount of energy used to raise the temperature of 1 g of water by 1 celsius Kinetic Energy is the energy in moving things Potential Energy is stored energy for example a compressed spring Equations Power Energy Time Kinetic Energy Equation E 1 2 mv Energy Energy is the ability to do work Can be active Kinetic Moving or stored Potential Mechanical Electrical Chemical Energy is measured in Joules Calories Kilowatt Hours BTU s and Quads which are 10 15 BTU s BTU s are usually used to measure the amount of energy the entire world uses per year When the economy grown energy use grows and Vice versa For example in the 2008 recession less energy was made and less was used Energy is always conserved when it changes forms First Law of Thermodynamics An explosion occurs when a great deal of stored energy is suddenly converted to heat in a confined space Batteries have low energy but a high kWh cost Forms of Energy Kinetic Energy is the energy in moving things Potential Energy is stored energy for example a compressed spring Nuclear Energy is the energy stored in the bonds of atoms Gravitational Energy is the energy that an object has at an high altitude Chemical Energy is the energy stored in the forces between atoms Heat is all forms of energy Kinetic Energy Kinetic Energy Equation E 1 2 mv 2 1 meter per second mps 2 miles per hour mph 1 kilogram kg 2 pounds lb Power Power is the rate of energy transfer Power plants just convert energy they never actually create it Energy cannot be created About 2 3rds of a power plants energy is lost in heat The brightness of a light build depends on how much power it uses 60 Watt bulbs 40 Watt bulbs etc Uranium The huge forces in the uranium atoms provide its high energy most atoms it is hard for this energy to be released but in uranium through chain reaction it is released very easily Coal Coal is dirt cheap Coal takes up less space and is less dense than gas Solar Panels The sun is a sustainable source of energy Solar panel power outputs 1 square meter of solar panel 1 kilowatt of sunlight 150 400 watts 1 square kilometer 1 gigawatt of sunlight 150 400 megawatts Smart Rocks A Smart Rock is a rock with a computer chip in it The rock will get in the way of missiles Used in ballistic missile defense From the missiles perspective the rock is coming at is very very fast Change in perspective is called classical relativity Things you may need Know Electric cars are pricer in the long run because of the cost of replacing the batteries Hybrid engines are very e cient they run on gasoline and electricity To recharge a fuel cell you give it more fuel while to recharge a battery you have to recharge it with electricity from elsewhere Electrolysis is when electricity is passed through water to produce hydrogen and oxygen 1 kilogram of hydrogen 1 gallon of gasoline energy wise Hydrogen is hard to store and transport and produces less energy than gas per area Hydrogen cannot be mined Book Quiz practice Questions Smart rocks are considered for geologic dating ballistic missile defense nuclear power solar power A B C D One watt is equivalent to one joule second one coulomb second one calorie second one horsepower A B C D The asteroid that killed the dinosaurs exploded because A B C D it was made of explosive material it was made out of U 235 it got very hot from the impact it didn t explode it knocked the Earth out of its normal orbit Kinetic energy can be measured in A watts B C D calories grams amperes Which of the following statements is true A B C D E Energy is measured in joules and power is measured in calories Power is energy divided by time Batteries release energy but TNT releases power Power signifies a very large value of energy All of the above For each of these mark whether it is a unit of energy E or power P horsepower power kilowatt hour energy A B C watt power D calorie energy Hybrid vehicles run on A B C D electric and solar power solar power and gasoline electric power and gasoline nuclear power and gasoline What is the main reason that hydrogen driven automobiles have not replaced gasoline ones A Hydrogen is too expensive B Hydrogen is too di cult to store in an automobile C Hydrogen is radioactive and the public fears it D Hydrogen mixed with air is explosive Compared to an equal weight of gasoline U 235 can deliver energy that is greater by a factor or choose the closest value 2200 25 000 one million one billion A B C D Which of the following contains the most energy per gram chocolate chip cookies A TNT B C battery D uranium Compare the energy in a kilogram of gasoline to that in a kilogram of flashlight batteries A The gasoline has about 400 times as much energy B The gasoline has about 10 times as much energy C The gasoline has about 70 times less energy D They cannot be honestly compared since one stores power and the other stores energy Which is least expensive for the same energy delivered The kinetic energy of a typical 1 gram meteor is approximately equal to the energy of A coal B gasoline C natural gas D AAA batteries A 10 grams of TNT B 150 grams of TNT C 1 100 grams of TNT D 10 grams of gasoline three or four decades A hundreds of years B C 72 years D less than a decade Coal reserves in the United States are expected to last for A limitation fro all electric automobiles is low energy density per battery A B Batteries explode more readily than gasoline C Electric energy is not useful for autos D Electric motors are less e cient than gasoline motors Solar power is about choose all that are correct A 1 watt per square meter B 1kW per square meter C 1 megawatt per square km D 1 gigawatt per square km The e ciency of inexpensive solar cells is closest to A 1 B 12 C 65 D 100 A 0 01 horsepower B 0 1 horsepower C 0 2 horsepower D 1 horsepower A 10 Calories B 50 Calories A human running up stairs can briefly use power of approximately A 12 oz can of soft drink not the diet or lite kind contains about The energy per gallon not per pound of liquid hydrogen compared to gasoline is about A large nuclear power plant delivers energy of about Electricity from a AAA battery costs the consumer about Electricity from a wall plug costs the consumer about C 150 Calories D 2000 Calories A 1 megawatt B …
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