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Energy dependence on observer framework 
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#1
Jun1314, 12:33 PM

P: 272

Does mechanical energy of a system depend on the framework of an observer (neglecting a constant)?



#2
Jun1314, 01:28 PM

Mentor
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#3
Jun1314, 02:37 PM

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Thanks
PF Gold
P: 39,682

I agree with Nugatory but I can't help but wonder what you mean by "neglecting a constant".



#4
Jun1514, 02:57 AM

P: 272

Energy dependence on observer framework
I clarify my purpose of the question: Newton's laws are only valid in inertial framework. I like to know whether energy formalism is valid in noninertial framework or not? In other words, can one solve the problems exactly, using conservation of energy in noninertial framework? 


#5
Jun1514, 05:29 AM

P: 127

[itex]\int_{t_0}^{t_1}\vec{F}(t)\cdot\vec{v}(t)dt = \frac{1}{2}m v^2(t_1)  \frac{1}{2}m v^2(t_0)[/itex] is valid in frames where [itex]\vec{F}(t) = m \frac{d\vec{v}(t)}{dt}[/itex] That is, in inertial frames. You still can use it in noninertial frames IF you add "inertial forces". [itex]\int_{t_0}^{t_1}\vec{F}(t)\cdot\vec{v}(t)dt = U(x(t_0),y(t_0),z(t_0)) U(x(t_1),y(t_1),z(t_1))[/itex] is valid in any frame where [itex]\vec{F}(x,y,z) = \nabla U(x,y,z)[/itex] where [itex]U(x,y,z)[/itex] does not vary with time in this frame. 


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