# Questions tagged [textbook-erratum]

For questions about possible specific errors in asker's reference material. PLEASE search for the relevant errata webpage before asking. DO NOT USE THE TAG for general critique beyond the scope of the reference.

241 questions
Filter by
Sorted by
Tagged with
3k views

### Error concerning projectile motion in respected textbook?

In the textbook Fundamentals of Physics by R. Shankar of Yale Open Courses, appears the following assertion pertaining to a car driving off a cliff, which seems correct: This is exactly how long it ...
93 views

### Lorentz force error in the present 2024 version of the gravitoelectromagnetism Wikipedia page? [closed]

I noticed that the Gravitoelectromagnetism (GEM) Wikipedia page has been edited recently. The factor of 4 in the GEM Lorentz force equation is now missing. But the GEM field equations are identical to ...
• 41
1 vote
60 views

### Definition of the Conformal algebra generators

In the textbook "Introduction to Conformal Field Theory" by Blumenhagen and Plauschinn (2009), Section 2.1, the generators of the Lie algebra corresponding to the conformal group for the ...
55 views

### Time component of four-velocity

While reading through Spacetime and Geometry by Sean Carroll, I came across the following passage: "Don't get tricked into thinking that the timelike component of the four velocity of a particle ...
• 442
110 views

• 793
1 vote
45 views

• 31
159 views

• 283
124 views

• 789
48 views

### Are the options correct of this question? [closed]

Q) An object is being pulled in the west with 50N force and in the east with 20N force. What will be the value of the net force? A) 53.85N B) 63.85N C) 43.85N D) 50.85N I feel that none of the options ...
• 1,018
174 views

### The Beta Function and the Bare Charge

According to "Introductory Lectures on Quantum Field Theory", by L. Álvarez-Gaumé and M. A. Vázquez-Mozo, (P. 84) the dependence of the bare charge $e_{0}(\Lambda)$ on the cutoff $\Lambda$ ...
1 vote
116 views

### Doubt in position operator acting on fourier transform, $\tilde{f}(k)$ of $f(x)$

I was solving a problem from the problem sets provided by MIT OCW. Here's the problem set. I was stuck in the problem 2(g) So, I looked at the solution to the problem and couldn't understand it. ...
• 349
272 views

### Possible error in Griffiths, Intro. to Electrodynamics, Problem 7.60

Probelm 7.60 of Griffiths' Introduction to Electrodynamics, 4th ed, says: Suppose $\mathbf J(\mathbf r)$ is constant in time but $\rho(\mathbf r, t)$ is not—conditions that might prevail, for ...
• 870
363 views

• 980
952 views

### Does this question have two answers correct?

A simple pendulum (whose length is less than that of a second's pendulum) and a second's pendulum start swinging in phase. They again swing in phase after an interval of $18$ seconds from the start. ...
• 212
442 views

### Induced e.m.f and the speed of the magnet. (A-Levels Physics)

When a magnet is moved into a coil of $50$ turns at $0.12$ m/s, an E.M.F. of $3.60$ V is generated into the coil. What will be the E.M.F. generated when the magnet is removed from the coil at $0.48$ m/...
187 views

### Inconsistency in Goldstein’s Lagrangians for Relativistic Point Particles?

In Goldstein’s Classical Mechanics (3rd edition), section 7.10 focuses on covariant lagrangians for point particles. Here, we begin by stating $$L=-mc\sqrt{x’_{\nu} x’^{\nu}}, \tag{7.162}$$ with ...
1 vote
143 views

### Kohn-Sham equations, Sakurai 3rd edition, possible typo?

In Sakurai's quantum mechanics book 3rd edition page 448, equation 7.88, the book writes "Kohn and Sham found a way to derive a self-consistent approximation scheme, based on single particle ...
• 789
303 views

### Is there a typo in Carroll's expression for the Christoffel symbol transformation formula?

On Section 3.2 of Carroll's Spacetime and Geometry, he works on the proof of how Christoffel symbols transform under a change of coordinate system, in order to the covariant derivative of a tensor ...
• 376
441 views

### Conformal Ward identities for local conformal algebra: error in textbook?

In Schottenloher's mathematically-oriented CFT textbook, "A Mathematical Introduction to Conformal Field Theory," Proposition 9.8 on page 160 states the conformal Ward identities for 2D CFTs ...
3k views

### College Board Problem: Conservation of Momentum -> Conservation of Energy in a Spring

In my AP Physics C class today, we ran into a problem written by College Board whose answer we disputed. The problem is as such : A block of mass $M=5.0 \ \mathrm{kg}$ is hanging at equilibrium from ...
335 views

• 36.4k
208 views

### Approximation Methods in Physics

There is this one statement in my physics textbook that I didn't quite get for finding out how much change in the time period of a pendulum occurs due to a small change in its length, due to thermal ...
• 152
125 views

• 1,488