jbriggs444's latest activity
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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... -
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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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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The light clock is really very simple. If you accept the invariance of the speed of light, then time dilation, length contraction and...
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jbriggs444 reacted to PeterDonis's post in the thread I The Einstein Clock aka Light Clock with
Like.
What else would be involved? No, they don't. The source can only be motionless with respect to one of them. Until you fix this... -
jbriggs444 reacted to Ibix's post in the thread How to increase phone signal strength by lying about it with Like.
"Mate, your signal strength is always better than mine. What network are you with?"
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jbriggs444 replied to the thread Chain falling out of a horizontal tube onto a table.There are a number of conundrums that deal with the unexpected behavior of falling ropes and chains. It seems clear that you are not...
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jbriggs444 replied to the thread I Why is the speed of light the same everywhere in the Universe?.You understand that "energy" is not an invariant quantity, right? The amount of kinetic energy in a thing depends on the frame of...
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This is in violation of the Joint WarnerBros/Hanna-Barbera/Disney Convention defining how female cartoon characters are to be depicted...
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jbriggs444 reacted to A.T.'s post in the thread A Please Explain Elementary Physics Elevator Question with Like.
The observable effects depend on all forces acting, not just on gravity. So it makes no sense to describe them as effects of gravity...
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jbriggs444 reacted to Herman Trivilino's post in the thread A Please Explain Elementary Physics Elevator Question with Like.
No, it's wrong. But explaining it repeatedly seems to have no effect. I told you to stop trying to generalize comments you read and...
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jbriggs444 replied to the thread A Please Explain Elementary Physics Elevator Question.I would accept that. Gravity is the force of gravity. It is given by ##F_g = \frac{Gm_1m_2}{r^2}##. It acts on ##m_1## in the direction...
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Polaris is "up" from the north pole. North is a direction along the surface of the Earth.
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One possibility, known as the Hartle-Hawking no boundary proposal, is that if you go backward in time towards the big bang, you reach a...
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A subthread on how the "speed of expansion" of a material object is defined has been moved to a separate thread in the relativity forum...
