jbriggs444's latest activity
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jbriggs444 reacted to PeroK's post in the thread Will anyone alive today see a permanent colony on the Moon or Mars? with
Like.
The problem is that no one knows how fast technology in a certain area will develop. Extrapolating from the past is not possible... -
jbriggs444 reacted to Dale's post in the thread Undergrad Why is SI taught in US university physics courses instead of cgs? with Like.
That depends on what you are measuring. It reduces the zeroes for particle physics. What I really wonder is why people went from CGS...
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jbriggs444 replied to the thread Find the acceleration of a block (some sort of double Atwood machine?).In line ##\LaTeX##:: ##a_1 = \frac{4 m_2 m_1 + m_0 ( m_1 - m_2 )} {4 m_2 m_1 + m_0 (m_1 + m_2)} g## Which should render as ##a_1 =...
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jbriggs444 replied to the thread Find the acceleration of a block (some sort of double Atwood machine?).If you are using an accelerating frame and pseudo-forces then those pseudo-forces should appear in your force balance equations. If...
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jbriggs444 reacted to Steve4Physics's post in the thread Find the acceleration of a block (some sort of double Atwood machine?) with Like.
Yes. Agree 100%. In case there's any confusion, I certainly wasn't (in Post #10) promoting the OP's (Post #1) approach. But in Post...
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jbriggs444 replied to the thread Find the acceleration of a block (some sort of double Atwood machine?).This is fine in isolation. One often picks a sign convention to try to keep all quantities positive. If one guesses wrong, the worst...
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jbriggs444 replied to the thread Undergrad Why is thermal energy treated differently than other kinds of energy?.Agreed. I like to point to Newton's original text from time to time. The second part is the one that really resonates with me. In...
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jbriggs444 reacted to Dale's post in the thread Undergrad Why is thermal energy treated differently than other kinds of energy? with Like.
That isn’t surprising given how poorly written your original post was. This one was much better These equations are incorrect. The...
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jbriggs444 reacted to cianfa72's post in the thread Undergrad Why is thermal energy treated differently than other kinds of energy? with Like.
Ok, you are assuming the inertial rest frame of the table. By Newton 3rd law, the book acts with a force on the table, so there must be...
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jbriggs444 reacted to kuruman's post in the thread Undergrad Why is thermal energy treated differently than other kinds of energy? with Like.
To @nataliaeggers: Let me elaborate a bit more along the lines presented by @jbriggs444. Suppose you have a collection of ##10^{24}##...
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jbriggs444 replied to the thread Undergrad Why is thermal energy treated differently than other kinds of energy?.No, that is not the frame that I implicitly chose. The table does move with respect to the table+book COM frame. The frame that I had...
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jbriggs444 replied to the thread Undergrad Why is thermal energy treated differently than other kinds of energy?.Newton's third law is all about momentum. It amounts to a statement that momentum is conserved. Newton's third law has less to do with...
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jbriggs444 reacted to kuruman's post in the thread Find the acceleration of a block (some sort of double Atwood machine?) with Like.
Did you notice that your expression cannot possibly be correct because its numerator is the negative of the denominator and simplifies...
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jbriggs444 reacted to BvU's post in the thread Find the acceleration of a block (some sort of double Atwood machine?) with Like.
:welcome: The picture is fine, but the hieroglyphs are more difficult.: is hard to decipher ... In PF you often get more questions...
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jbriggs444 replied to the thread Find the acceleration of a block (some sort of double Atwood machine?).I had to zoom way in to read the handwriting. Your first assertion is that ##a_1 + a_2 = 2a_k##. This is obviously correct. The...