brotherbobby's latest activity
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brotherbobby replied to the thread Problem with pulleys - two fixed and one movable.Because the force of the rope is not the only force that acts on them. There's the force of gravity (weight) too, which is different for... -
brotherbobby replied to the thread Problem with pulleys - two fixed and one movable.That is what I have a problem with. If it is the same (inextensible) rope, how can different parts of it move with different...
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brotherbobby posted the thread Problem with pulleys - two fixed and one movable in Introductory Physics Homework Help.[The problem involves the use of Lagrange's equations for conservative systems. I am first trying to solve it using Newton's mechanics...
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brotherbobby replied to the thread Independent components of three indexed systems ##T_{ijk}##.Thank you @julian , while I am struggling to understand your method, especially that of the "stars and bars", your results are precious...
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brotherbobby posted the thread Independent components of three indexed systems ##T_{ijk}## in Calculus and Beyond Homework Help.Attempt : [The author uses the term "system" with respect to indexed quantities. He reserves the term "tensor" when the components of...
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brotherbobby replied to the thread I Visualising rotation in 3-D space.That looks extremely good. I am still struggling with the problem and, despite your efforts, I might continue to do so. Still, thank you...
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brotherbobby replied to the thread I Visualising rotation in 3-D space.I could visualise what you mean. So thank you for that. Indeed, the ##x## axis starts with a precise angle to the axis of rotation and...
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brotherbobby replied to the thread I Visualising rotation in 3-D space.Euler's angles are useful in that they help you find the answer. But you don't get a feel of "how" in real time. I'd like a way to...
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I have very little clue as to how to imagine (visualise) the rotation and how the axes will look. All I can do is to draw the image of...
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brotherbobby replied to the thread Writing a vector parallel and normal to a unit vector ##\hat n##.Brilliant argument. Better than using the BAC-CAB rule which you referred to earlier. Still, there's an element of brilliance in that...
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brotherbobby replied to the thread Writing a vector parallel and normal to a unit vector ##\hat n##.Ok you mean the BAC CAB rule in reverse. That will require some thinking. To derive or imagine the double cross product on the RHS...
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brotherbobby replied to the thread Writing a vector parallel and normal to a unit vector ##\hat n##.Yes. I know what's going on. But this is not the time to apply this rule. Because it involves what's in the answer which I am supposed...
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brotherbobby replied to the thread Writing a vector parallel and normal to a unit vector ##\hat n##.I know what you did. I am asking where did you get the vector ##\hat n\times(\mathbf A\times \hat n)## from?
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brotherbobby replied to the thread Writing a vector parallel and normal to a unit vector ##\hat n##.Where did you obtain the first term from : ##\hat n\times(\mathbf A\times \hat n)##?
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brotherbobby replied to the thread Writing a vector parallel and normal to a unit vector ##\hat n##.Unit vector, you mean. Only one unit vector is given. I agree with you. There are two unit vectors as I show here but the decomposition...
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