I set up this problem this way:
##p_a^{\mu}=(E, \sqrt{E^2-m^2}, 0, 0)##
##p_b^{\mu}=(m, 0, 0, 0)##
##p_c^{\mu}=(2E_\gamma, 2E_\gamma, 0, 0)##
I have chosen to consider the two photons as a single particle of energy equal to ##2E_\gamma##. At this point I applied conservation of the...
Physicist Joseph Polchinski wrote an article (https://arxiv.org/pdf/1412.5704.pdf) where he considered the possibility that all symmetries in nature may not be fundamental. He says at page 36:
"From more theoretical points of view, string theory appears to allow no exact global symmetries, and...
since there is no external force in the x-direction linear momentum can be conserved. Hence I get the equation $$0 = mv^2 - 9mV^2$$
where ##v## is the velocity of B towards the right and ##V## is the velocity of A toward the left.
also the conservation of energy gives $$1/2(9m)V^2 + (1/2)mv^2 =...
Since there are no external forces, the angular momentum (##L##) and linear momentum (##P##) are conserved.
Let's call the left rod ##A## and the right one ##B##.
If all the balls were fixed, I'd write
##L_0=L_f##
##L_A+L_B=(I_A+I_B)\omega_f##
From this equation I can find the final angular...
Hello
I've written that homework statement as an example to illustrate my doubt:
How can I tell if a force is conservative or not?
I've read that, if the curl of the force is 0, it's conservative. But what about the friction force (##f=\mu N##)? Its curl is also zero, but it's not conservative...
I got the I3 values for the tau(minus) to be -1, as charge is -1 and Y=0. For muon(minus) i got I3 to be -1 too using the same equation and the anti electron neutrino to have an isospin of zero (since Q=0, Y=0). This shows I3 to be conserved (which is needed for strong interaction i believe)...
My initial thought was to use the conservation of energy law since there're no external forces acting on the system bullet + rod. The rod is in rest, the bullet is moving. Then after the collision, the bullet and the rod are rotating around the pivot together, so the kinetic energy of the bullet...
In Newtonian mechanics, conservation laws of momemtum and angular momentum for an isolated system follow from Newton's laws plus the assumption that all forces are central. This picture tells nothing about symmetries.
In contrast, in Hamiltonian mechanics, conservation laws are tightly...
I attempted the solution using force method. I got correct. However, I was stuck at the alternative way to solve problem using energy method. As shown in screenshot 2, he tells that the energy of system changes due to 2 ways:
- The tension T
- Leaking of mass
As shown in screenshot 2 ,the...
A while back I thought of an issue with parallel charged plates. Imagine this: a set of opposite charged resistive plates with holes in the center. In theory, there is a finite amount of energy required to push a positive charged particle through the hole in the positive plate (in theory it...
$$mg(0.45) = mg(R + R \cdot cos(\frac{π}{3})) + \frac{1}{2}mv^2$$
$$v^2 = g(0.9 - 3R)$$
The centripetal acceleration during the "flying through air" will be given by gravity
$$mg \cdot cos(\frac{\pi}{3}) = \frac{mv^2}{r}$$
$$R = \frac{1.8}{5}$$
But my book says $$ R = \frac{1}{5}$$
Hi all,
The scenario I'm considering is a solid sphere (of uniform density) rotating with constant angular velocity when it abruptly splits into two hemispheres along a cut which contains the rotation axis. The hemispheres will begin to separate; if, for example, we consider the rotation to be...
This theorem is summarized here: https://en.wikipedia.org/wiki/Coleman%E2%80%93Mandula_theorem
I sort of understand the mathematical content of the theorem, that
But what I don't understand is, intuitively, what sort of possibilities are ruled out. I've heard it said that flavor conservation...
Homework Statement
Two images are attached. The first image details the problem. The second image has an x',y' coordinate system depiction of the problem.
Homework Equations
The total energy of a particle is defined as E = mc^2, with m = γ*m_0.
The Attempt at a Solution
If the x', y'...
My question is related to the book: Classical Mechanics by Taylor. Section 7.8
So, In the book Taylor is trying to derive the conservation of momentum and energy from Lagrange's equation. I understood everything, but I am struggling with the concept and the following equation...
Homework Statement
Consider 2 balls A,B on the same line . and they are connected to a third one G with a rope L. AG, AB. now the system monves in the effect of the mass of G and its projection to the line AB is in the middle. No friction. mass of A=mass of B=m and mass of G=2m
.FInd the time...
Homework Statement
Consider 2 balls A,B on the same line . and they are connected to a third one G with a rope L. AG, AB. now the system monves in the effect of the mass of G and its projection to the line AB is in the middle. No friction. mass of A=mass of B=m and mass of G=2m
.FInd the time...
Homework Statement
The questions showed in the pictures ask me whether the collisions in the drawings could be elastic or inelastic, I am not given any mass, the angles are a little vague but I think B and C are supposed to be π/2 and π respectively. For velocity, I am just given the direction...
The equation of motion for a charged particle with mass ##m## and charge ##q## in a static magnetic field is:
##\frac{d}{dt}[m{\dot{\vec{r}}}]=q\ \dot{\vec{r}}\times \vec{B}##
From this, we can see that ##\frac{d}{dt}[m\dot{\vec{r}}-q \vec{r}\times \vec{B}]=0##
and so the following quantity is...
I don't know much about classical physics(such as lagrangian function), but as i was reading conservation of energy, i came to this theorem and it tells that if a system is symmetrical in certain transformations(such as translation, rotation etc) then it will have a corresponding law of...
If a (polarized) photon is absorbed by a polarization filter, does its energy go into the filter?
I am wondering if that is the case to obey conservation laws.
And if it passes, is its original polarisation direction somehow conserved?
Hi everyone,
I was watching Susskinsd's lectures posted on youtube about Quantum mechanics and he started explaining his -1st basic law of physics saying: the conservation of information means basically that if you start with 2 quantum states (vectors) which are observably different, or...
I believe that conservation laws, like for energy and momentum, are obeyed during the particle decay process, e.g. the total energy of the new output particles is equal to the energy of the one input particle. But is that relationship subject to quantum fuzziness? Suppose we, somehow, prepare...
English is not my native language. So, I hope to be understood. :-)
The Compton effect is the dynamics in which high-energy incident photons (X or gamma) are scattered by electrons of certain materials, like graphite. The electrons are supposed to be free, as they are only weakly bounded by...
Homework Statement
A tennis ball and basketball are dropped from a height of 1m (the tennis ball on top of the basketball). The tennis ball has a mass of 75g and the basketball has a mass of 1kg. When dropped separately, the tennis ball bounces to a height of 0.5m and the basketball to a...
Homework Statement
Consider the Kortweg-de Vires Equation in the form
$$\frac{\partial \psi}{\partial t}+\frac{\partial^3 \psi}{\partial x^3}+6\psi\frac{\partial \psi}{\partial x}=0$$
Find the relation between the coefficients ##c## and ##d## , such that the following quantity is conserved...
The decay processes of the ##W## bosons are completely governed by the charged current interaction terms of the Standard model:
$$\mathcal{L}_{cc}
= ie_{W}\big[W_{\mu}^{+}(\bar{\nu}_{m}\gamma^{\mu}(1-\gamma_{5})e_{m} + V_{mn}\bar{u}_{m}\gamma^{\mu}(1-\gamma_{5})d_{n})\\...
Homework Statement
The air-track carts in the figure(Figure 1) are sliding to the right at 2.0 m/s. The spring between them has a spring constant of 140 N/m and is compressed 4.1 cm. The carts slide past a flame that burns through the string holding them together.
What is the final speed of...