14 votes

What is the correct formulation of Newton's Second Law of Motion?

Your product rule is incorrect without being handled properly. The expression $F=v\frac{\text dm}{\text dt}+m\frac{\text dv}{\text dt}$ does not follow Galilean relativity; $v$ is not the same for ...
BioPhysicist's user avatar
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10 votes

What is the correct formulation of Newton's Second Law of Motion?

Although mathematically inequivalent, the two definitions are equivalent within the scope of Newtonian Mechanics. To understand the previous statement, one must understand the meaning of the ...
GiorgioP-DoomsdayClockIsAt-90's user avatar
7 votes

Why did Peter Higgs, et al. suspect that the $W$ boson(s) had mass? All the way back in 1963, '64?

Already in 1957, Julian Schwinger, Annals of Physics 2 (5) November 1957, pp 407-434, "A theory of the fundamental interactions", had inferred from the chiral structure and puny strength ...
Cosmas Zachos's user avatar
5 votes

What is the correct formulation of Newton's Second Law of Motion?

They are equivalent, because it is assumed (in both) that the body does not lose or gain any massive parts. In case the body is losing massive parts, such as a rocket, both formulations seem ...
Ján Lalinský's user avatar
5 votes

Does a massless boson imply an infinite interaction distance?

Using the basic formulae $$\Delta \frac{1}{r}=-4\pi \delta^{(3)}(\vec{x}) \quad \text{with} \quad r=|\vec{x}| \tag{1}$$and $$\Delta \frac{f(r)}{r} =\frac{f^{\prime \prime}(r)}{r} \quad \text{for}\quad ...
Hyperon's user avatar
  • 6,038
2 votes

How does this term in the Majorana mass not vanish?

Remember that $\nu_L$ is a two-component column vector with Grassmann entries $\nu_L^1$ and $\nu_L^2$, so with $$ \sigma_2 =\left[\matrix{0&-i\cr i&0}\right], $$ we have $$ \nu_L^T \sigma_2 \...
mike stone's user avatar
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2 votes

Maxwell equations associated to a massive photon

Maxwell homogeneous equations remain the same, because they are source-free: $$\boldsymbol{\nabla}\times \boldsymbol{E} = -\frac{\partial \boldsymbol{B}}{\partial t} \tag{1}$$ $$ \boldsymbol{\nabla}\...
Sancol.'s user avatar
  • 685
1 vote

What is the correct formulation of Newton's Second Law of Motion?

For a collection of particles, you have the definition of momentum $$ \boldsymbol{p} = \sum_i m_i \boldsymbol{v}_i \tag{1}$$ for which you can show that for a rigid body there exists a point C riding ...
John Alexiou's user avatar
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1 vote

Why did Peter Higgs, et al. suspect that the $W$ boson(s) had mass? All the way back in 1963, '64?

In 1961, Sheldon Lee Glashow already published his paper with the correct EW symmetry group SU(2)$\otimes$U(1) and hypothesized the W and Z bosons. The question, traced back to Julian Schwinger (...
Jon's user avatar
  • 3,828

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