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8th Enery and Power
PHYSICAL SCIENCE FOR CH 5
| Question | Answer |
|---|---|
| the ability to do work or cause change? | energy |
| what are two kinds of energy? | kinetic and potential energy |
| the energy of motion? | kinetic energy |
| the kinetic energy of an object depends both on its? | mass and its velocity |
| kinetic energy increases as? | velocity increases |
| what is the formula for kinetic energy? | mass x velocity2 divided by 2 |
| doubling an objects velocity will___ its kinetic energy. | quadrupled |
| energy that is stored and held in readiness? | potential energy |
| what is the potential energy called that is associated with objects that can be stretched or compressed? | elastic potential energy |
| what is potential energy called that depends on height? | gravitational potential energy |
| what is the formula for gravitational potential energy? | weight x height |
| t or f the greater the height of an object, the greater its gravitational potential energy. | true |
| the energy associated with the motion or position of an object? | mechanical energy |
| the total energy of particles in a substance or material? | thermal energy |
| t or f when the thermal energy of an object increases, its particles move faster. | true |
| the potential energy stored in chemical bonds that hold chemical compounds together is called? | chemical energy |
| what kind of energy is stored in the foods we eat? | chemical |
| the energy that moving electric charges carry is called? | electrical energy |
| what kind of energy is stored in the nucleus of an atom? | nuclear energy |
| examples of mechanical energy? | school bus ride, frog leaping, sounds you hear |
| examples of thermal energy? | ice cream, ice |
| examples of chemical energy? | chocolate, wood, wax |
| examples of electrical energy? | batteries, power lines, radios |
| examples of electromagnetic energy? | microwaves, infrared radiation, ultraviolet radiation. |
| examples of nuclear energy? | power plants, nuclear fushion |
| a change from one form of energy to another? | energy conversion |
| t or f most forms of energy can be converted into other forms | true |
| what kind of energy increases as its height increases? | potential energy |
| what kind of energy increases and what kind of energy decreases? | potential energy decreases and kinetic increaes |
| when one form of energy is converted to another, no energy is destroyed in the process< | the law of conservation of energy |
| friction converts mechanical energy to ___ energy? | thermal |
| t or f matter and energy can be converted back and forth? | true |
| t or f a fuel is a material that stores chemical potential energy? | true |
| examples of fossil fuels? | coal,petroleum, and natural gas |
| what did the energy in fossil fuels originally come from? | the sun |
| how is the potential chemical energy of fossil fuels released? | they burn to release potential chemical energy |
| the process of burning fossil fuels is known as? | combustion |
| the mechanical energy of turbines is converted into electrical energy by? | generators |
| the rate at which work is done or the amount of work done in a unit of time? | power |
| what is the formula for power? | work divided by time |
| another way to calculate power? | force x distance divided by time |
| 1 j/s= 1? | watt |
| t or f power is often measured in larger units than watts? | true |
| 1 kilowatt=? | 1000 watts |
| t or f an electric power plant produces millions of kilowatts. | true |
| power is the___ at which energy is transferred from one object to another or converted from one form to another? | rate |
| 1 horsepower=? | 746 watts |
| 25 N x 10 m=? | 250j |
| 5000N x 15m/ 3s=? | 25000 watts |