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3 votes
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Is the answer given in the option wrong?

The answer sheet is correct. You are ignoring the statement “The direction of the motion of the object changed only once, at time t.” That means that the velocity was zero at time t. So before time t ...
Dale's user avatar
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2 votes

Derivation of Schrödinger equation in Feynman-Hibbs

Briefly speaking, it follows from dimensional analysis that higher-order terms ${\cal O}(\eta^{n\geq 3})$ will [after the Gaussian $\eta$-integration (4.5)] only produce higher-orders terms ${\cal O}(\...
Qmechanic's user avatar
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0 votes

Precise relation between temperature change and physical quantities

$$ \frac{l_1}{l_2}=\frac{1+\alpha\theta_1}{1+\alpha\theta_2} \implies > l_2 = l_1\frac{1+\alpha\theta_2}{1+\alpha\theta_1} $$ The equations above give us two different answers for lengths at a ...
Bob D's user avatar
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16 votes

In equation (3) from lecture 7 in Leonard Susskind’s ‘Classical Mechanics’, should the derivatives be partial?

The notation is a little sloppy from a purely mathematical point of view (although common in physics) so it might be causing a little confusion. To help clarify, it might help to use different letters ...
Andrew's user avatar
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3 votes

In equation (3) from lecture 7 in Leonard Susskind’s ‘Classical Mechanics’, should the derivatives be partial?

They are partial derivatives. From the chain rule, we have $$ \frac{\partial V(aq_1-bq_2)}{\partial q_1}= a V'(aq_1-bq_2),\\ \frac{\partial V(aq_1-bq_2)}{\partial q_2}= -b V'(aq_1-bq_2). $$ For ...
mike stone's user avatar
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2 votes

In equation (3) from lecture 7 in Leonard Susskind’s ‘Classical Mechanics’, should the derivatives be partial?

No. The notation means that the V on the RHS is a function only of one variable, and so its derivative is the simplest, one-variable derivative.
naturallyInconsistent's user avatar
0 votes

Equivalence between Hamiltonian and Lagrangian Mechanics

Lagrangian and Hamiltonian mechanics are not exactly equivalent because they do not cover the same possibilities for the system to be described. Actually, just using the Newtonian laws gives yet ...
Jos Bergervoet's user avatar

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