jbriggs444's latest activity
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jbriggs444 replied to the thread Chain falling out of a horizontal tube onto a table.The claim that ##\vec F_\text{ext}## is given by ##\lambda hg(-\hat j) + \lambda \frac {\Delta x}{\Delta t}v \hat j## is clearly... -
jbriggs444 replied to the thread Chain falling out of a horizontal tube onto a table.I agree completely. The chain traverses a one dimensional fixed path. There is no net force nor freedom to move other than along the...
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jbriggs444 reacted to haruspex's post in the thread Chain falling out of a horizontal tube onto a table with
Like.
I alluded to that in post #44, but I think it is ok because we can instead view it in terms a tension transmitted around the curve and... -
jbriggs444 replied to the thread Chain falling out of a horizontal tube onto a table.It could if, for instance, we let the chain ride in a frictionless tube on the table. Then the section of chain in the tube would be...
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jbriggs444 reacted to haruspex's post in the thread Chain falling out of a horizontal tube onto a table with Like.
Since the problem statement does not specify what happens to the chain on reaching the table we have to make a reasonable guess about...
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jbriggs444 reacted to PeroK's post in the thread Undergrad Is calling fictitious forces "not real" just about terminology? with Like.
That's nearer to what I would say. But, if someone wants to say pushing a wall and the wall pushing back is cause and effect, then I'm...
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jbriggs444 replied to the thread Undergrad Is calling fictitious forces "not real" just about terminology?.Correlation is not the same as causation. I would say that it is possible for some state of affairs to "cause" a Newton's third law...
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jbriggs444 replied to the thread Chain falling out of a horizontal tube onto a table.I had considered offering this as a supposed equivalence. But it is not quite right. The portions of the chain that are falling through...
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jbriggs444 replied to the thread Chain falling out of a horizontal tube onto a table.Chains buckle under compression. Like cables, ropes, cords, strings and threads. The intent of the problem is clearly that the chain...
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jbriggs444 reacted to PeroK's post in the thread Undergrad The Einstein Clock aka Light Clock with Like.
PS note that it is the speed of light that is independent of the motion of the source. Not the velocity of light, which is a vector and...
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jbriggs444 reacted to haruspex's post in the thread Chain falling out of a horizontal tube onto a table with Like.
Whether it’s a track over a smooth shoulder or a massless pulley is clearly independent of whether the problem concerns a massless...
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jbriggs444 replied to the thread Chain falling out of a horizontal tube onto a table.The tube is smooth (frictionless). The mouth of the tube acts like an ideal pulley. The direction of the tension force changes there...
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jbriggs444 replied to the thread Chain falling out of a horizontal tube onto a table.I do not understand. There is no discontinuity in tension at the end of the tube where the chain turns downward. The obvious boundary...
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jbriggs444 reacted to Ibix's post in the thread Undergrad The Einstein Clock aka Light Clock with Like.
Just think about that for a minute. You are standing by the road and a passing car turns on its turn indicator. How are you and the...
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jbriggs444 reacted to PeroK's post in the thread Undergrad The Einstein Clock aka Light Clock with Like.
The light clock is really very simple. If you accept the invariance of the speed of light, then time dilation, length contraction and...