# Tag Info

Accepted

### 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 ...
• 103k

### 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}(\...
• 207k

### 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 ...
• 73.7k

### 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 ...
• 51.2k

### 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 ...
• 54.5k