Talk:Energy and work: Difference between revisions
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(Created page with "I have a problem with what this teaches. The way I learnt it is this Work: Applied force x movement in Joule. It's the transferred amount of energy, not stored energy. ...") |
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Ex: We lift an object of 10kg to 10m high, 1000J of work is done to do this. | Ex: We lift an object of 10kg to 10m high, 1000J of work is done to do this. | ||
Energy: The ability to do work - Not the flow of work. Rather it should be the other way around: Work is the | Energy: The ability to do work - Not the flow of work. Rather it should be the other way around: Work is the displacement of energy. | ||
Ex: To be able to lift the object that high, we need to have at least 1000 J of energy somewhere in our system to be able to do it. If we don't have the energy in the system, we can't do it. | Ex: To be able to lift the object that high, we need to have at least 1000 J of energy somewhere in our system to be able to do it. If we don't have the energy in the system, we can't do it. If we do, we transfer this energy into the object. | ||
Power: The rate at which work is done and equals the rate at which energy is transferred. | Power: The rate at which work is done and equals the rate at which energy is transferred. | ||
Ex: You need to use 1000kJ, which you do in 10 seconds, meaning you use an average of 100W to lift the object to 10m high. | Ex: You need to use 1000kJ, which you do in 10 seconds, meaning you use an average of 100W to lift the object to 10m high. | ||
(all examples are at 100% efficiency of course) | (all examples are at 100% efficiency of course) | ||
Revision as of 08:37, 29 January 2015
I have a problem with what this teaches. The way I learnt it is this
Work: Applied force x movement in Joule. It's the transferred amount of energy, not stored energy.
Ex: We lift an object of 10kg to 10m high, 1000J of work is done to do this.
Energy: The ability to do work - Not the flow of work. Rather it should be the other way around: Work is the displacement of energy.
Ex: To be able to lift the object that high, we need to have at least 1000 J of energy somewhere in our system to be able to do it. If we don't have the energy in the system, we can't do it. If we do, we transfer this energy into the object.
Power: The rate at which work is done and equals the rate at which energy is transferred.
Ex: You need to use 1000kJ, which you do in 10 seconds, meaning you use an average of 100W to lift the object to 10m high.
(all examples are at 100% efficiency of course)