haruspex's latest activity
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haruspex replied to the thread Undergrad Why is thermal energy treated differently than other kinds of energy?.Not sure what Newton III has to do with energy. Please elaborate. Thermal energy is just disordered kinetic energy. Can you be more... -
haruspex replied to the thread Undergrad Is a half submerged object submerged in its own displaced water?.Revised post: As @Baluncore reminded me, ‘displacement' in this context does not have its every day meaning. The displacement of an... -
haruspex replied to the thread Undergrad Is a half submerged object submerged in its own displaced water?.Yes, my mistake… I was using displacement to mean the volume that was occupied by water and now isn’t, which is not the definition... -
haruspex replied to the thread Find the acceleration of a block (some sort of double Atwood machine?).@michelp: Further to @jbriggs444 response in post #2, it helps readers greatly if you define your variables up front, particularly in... -
haruspex replied to the thread Undergrad "Alien objects", Stillwell's "Reverse Mathematics".Isn't that dropping an axiom? I don’t see how it is 'strengthening' one. But then, going from real to complex is adding a closure... -
haruspex replied to the thread Undergrad Why is water pressure increased in a plastic bag in a bucket?.Certainly in the videos corresponding to case D that is true, but it is not clear to me whether it applies in any actual experiment that... -
haruspex replied to the thread Undergrad Why is water pressure increased in a plastic bag in a bucket?.That's one of the only two ideas I had. The video shows the water being poured over the top, but there could still be dry patches... -
haruspex replied to the thread Vector calculus: line element dr in cylindrical coordinates.@deananderson , Just in case it is still not clear from the various responses above, they can be synthesised as: ##\vec... -
haruspex reacted to Janus's post in the thread Convert Circular motion into figure-8 shaped loop with
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Since the original animation was just to show the basic idea, I didn't include those types of restraints as it would be simple to do... -
haruspex replied to the thread Undergrad "Alien objects", Stillwell's "Reverse Mathematics".Do you mean, when you omit an axiom? -
haruspex replied to the thread Convert Circular motion into figure-8 shaped loop.I think there'd be a practical problem with the orthogonal arrangement. When the horizontal bars are at the 3 o'clock/9o'clock... -
haruspex replied to the thread How do I derive an expression for the velocity vector for any α?.The exact wording suggests that is the intention. This is reinforced by its asking for the velocity vector, not the speed. If we only... -
haruspex replied to the thread Difficulty understanding the reasoning behind constraint equations in mechanical systems.… has to be assumed to be constant (or we do not have enough information) … an idealised mechanical system is often assumed to consist of.. -
haruspex replied to the thread How do I derive an expression for the velocity vector for any α?.And at that point, ##s=\pi/\alpha##. When will ##s## exceed that? -
haruspex replied to the thread Undergrad Understanding permutations and combinations in a coin toss experiment.Enumeration problems do not, in general, fall neatly into just the two categories. See https://en.wikipedia.org/wiki/Twelvefold_way.