# All Questions

2 views

### Are there any issues connecting Neutral and Live at once to the supply line?

This is related to electrical engineering. A normal plug point has the wiring structure of the normal cct diagram I've drawn below. I'm thinking about plugging a device into the outlet in a permanent ...
38 views
+50

### What determines a particles probability of creation?

I know when we're discussing events at a quantum level, we deal in probability and not absolutes. What I'm looking to understand, is when articles I've read on particle physics state a particle has a ...
1 view

### Constant RPM of Gas Compressor

I would like to clear out my understanding of gas compressor. If it is moving at constant RPM, is it mean that it can only allow same volumetric flow rate all the time? So the power will remain ...
694 views

### What is the definition of particle-hole symmetry in condensed matter physics?

People often talk about particle-hole symmetry in solid state physics. What are the exact definition and physics picture of particle-hole symmetry? How to define the density of particles and holes?
68 views

### Difference of connections in the Killing vector equation

For the Killing vector equation, I sometimes see it written in terms of spin connection $\omega$ and other times in terms of the affine connection $\Gamma$. What is the difference between the two ...
94 views

### Gravitational potential in GR

In proving that the metric will play the role of gravitational potential, there is this chain of ideas: ...
88 views

### What experience tells us that gravitational acceleration cannot vanish everywhere?

In attempt to describe the consequences of the Equivalence Principle: When there are gravitational accelerations present, as for example in the gravitational field of the earth, the space cannot be ...
95 views

### Solve unsteady state Bernoulli equation for flow in a pipe

I am an engineer studying an unsteady-state flow through a pipe. The Pipeline has been cleanly cut into two halves, without deforming the cylindrical form of the pipe, exposing the contents to ...
16 views

### Why the rear wheels of vehicle is a bit larger than the front ones? [on hold]

for example, I have found it in a tractor and racing car. Is it for getting more rectilinear speed for same angular speed?
123 views

### Scale invariance in QFT?

About scale invariance in "beyond the standard model". At the base of the analysis is the principle of scale invariance. So what is being said: what if there were another sector of the theory that ...
14 views

### How will the Milky Way / Andromeda combined galaxy appear in 4 billion years?

In 4 billion years, do we we have an idea of what the combined Milky Way and Andromeda galaxy pairing will look like? In particular, will the presumed black hole at the centre of our galaxy, (and I ...
48 views

### Newtonian motion of a particle confined to a smooth surface

Recently, I've been considering a model wherein a lone particle with constant mass m is confined to a surface $F$: $\mathbb{R}^m \to \mathbb{R}^n$ , where $m < n$. I declare this surface to be ...
252 views

112 views

### Induced Current & Lenz's Law - 2 Circular Loops with same direction of current

I'm new to the wonderful world of physics, and I'm really confused about magnetism and induced currents. Let's say we have 2 circular closed loops that each carry a current $I$ clockwise and the ...
12 views

### Find the angle when lower mass loses contact with ground

Consider the following simplified model of a skater falling over: Two equal masses $m$ are attached to opposite ends of a light, straight rod of length 2. One mass rests at $(0,0)$ on a ...
91 views

### Forces Create Angular Acceleration And “Straight” Acceleration - But How Much Of Each?

Let me set up the following problem for a rectangle floating in space: We know its dimensions. We know its mass. There's a force pushing it for a known amount of time - we know the angle & ...
50 views

### Quantum Gravity [on hold]

By the Pauli exclusion principle fermions cannot occupy the same space, cannot have identical quantum numbers. The bosons however can. We also know that the universe, and in particular the various ...
23 views

### Increase of an electron's (relativistic) mass

Considering the equivalence of mass and energy, is we want to increase the (relativistic) mass of an electron 1000 times, should we give it 5*10^5 * 1000 = 5*10^8 eV of Kinetic energy => 1001 electron ...
300 views

### A student of mine wants to build a gyroscopic inertial thruster

I work as a tutor with students in their first three semesters. One of my more eager students is obsessed with the gyroscopic inertial thruster . Here is a Wikipedia article on it. I was not able to ...
3k views

### Why, when one opens 1 car window, does that noise occur?

When you're driving and you open 1 car window, say the front one, there comes a horrible noise, but when you open another window just the slightest bit, this noise goes away (I'm sure most people know ...
21 views

### How does gravity and velocity affect the time we see on our watches?

I had heard about the fact that the gravity we experience makes a difference in the time in our watches and also our velocity when it is close to c (speed of light). Can anyone please elucidate how it ...
16 views

### Potential difference in a circuit of n cells = 0? How?

I was supposed to find the potential difference across any one cell in an arrangement consisting of n cells of EMF E connected in series in a closed circuit and internal resistance r. I proceeded by ...