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183_notes:internal_energy [2018/05/29 21:42] – hallstein | 183_notes:internal_energy [2021/04/15 16:58] – [Systems With Structure Can Have Internal Energy] stumptyl | ||
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===== Internal Energy ===== | ===== Internal Energy ===== | ||
- | Up to now, you have read about systems that have no internal structure: [[183_notes: | + | Up to now, you have read about systems that have no internal structure: [[183_notes: |
==== Lecture Video ==== | ==== Lecture Video ==== | ||
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[{{183_notes: | [{{183_notes: | ||
+ | \\ | ||
- | Until now, you have considered systems of point particles, which have no internal structure. You will now relax that condition. | + | __//Until now, you have considered systems of point particles, which have no internal structure. You will now relax in that condition.//__ |
- | Consider two systems of two particles (each of mass $m$) attached by a spring ($k_s$) moving to the left with a speed $v$ (figure to left). For one of the systems, the spring is at its relaxed length. For the other, the spring is compressed by a //massless// string tied around the objects. Which system has more energy? | + | Consider two systems of two particles (each of mass $m$) attached by a spring ($k_s$) moving to the left with a speed $v$ (figure to left). For one of the systems, the spring is at its relaxed length. For the other, the spring is compressed by a massless string tied around the objects. Which system has more energy? |
- | Clearly, both have the same kinetic energy ($K=\dfrac{1}{2} (M) v^2$; $M$ is the total mass of the system). But what about the energy associated with spring compression that is internal to the system? The object with the compressed spring has more //internal energy//. These are the kinds energy distinctions that you will need to make when objects have structure. | + | Clearly, both have the same kinetic energy ($K=\dfrac{1}{2} (M) v^2$; $M$ is the total mass of the system). But what about the energy associated with spring compression that is internal to the system? The object with the compressed spring has more //internal energy//. These are the kinds of energy distinctions that you will need to make when objects have structure. |
- | === Internal | + | ==== Internal |
{{ 183_notes: | {{ 183_notes: | ||
{{ 183_notes: | {{ 183_notes: | ||
- | You have already seen one form of internal energy (i.e., when a spring is compressed). It can be useful to be able to unpack the different forms of internal energy to work on a particular problem of interest. An object that is rotating about its center of mass will have internal energy associated with rotation: | + | You have already seen one form of internal energy (i.e., when a spring is compressed). It can be useful to be able to unpack the different forms of internal energy to work on a particular problem of interest. An object that is rotating about its center of mass will have internal energy associated with rotation: |
As you [[183_notes: | As you [[183_notes: |