# All Questions

134,906 questions
19 views

### Simple argument for Melia's linearly expanding Universe [on hold]

Here is a simpler version of my argument for Fulvio Melia's linearly expanding Universe. The Universe is assumed to be isotropic around every point P. Therefore, in Newtonian terms, the net ...
54 views

### How is mass of neutron compared with proton when it is inside the nucleus?

The mass of free neutron is around 0.1% more than the mass of proton. When it is bound inside the nucleus, neutron mass is less compared to its mass in free state. The question is how much mass it ...
30 views

### Why are displacements added algebraically during interference of waves , why not vectorially?

In the diagram (A) , the individual waves are crossing at an angle to each other , so the dispacemnt of the particle at their intersection must have an angle between them , and that must involve ...
41 views

### Not parabolic falling

Suppose a small mass m is launched from height h with horizontal initial speed v0; if the ground is horizontal, it's easy to calculate the equation of movement (parabolic), because the coordinates of ...
28 views

### Quantum Measurement in Different Basis [duplicate]

How can you make measurements on a qubit that is in a different basis than your measurement qubit? (i.e. You want to measure a single qubit in the $|+\rangle$/$|-\rangle$ basis but you can only make ...
17 views

### 24a battery on a an engine that needs 14a only? [on hold]

Can you actually use an 24a battery on an engine that was made for a 14a battery using resistors ?
43 views

### Name of the matrix that appears in matrix form of Hamilton's equations of motion

Consider a harmonic oscillator described by the second order differential equation $$\ddot{\phi} + \omega_0^2 \phi = 0 \, .$$ Defining $v \equiv \dot \phi$ we get two simultaneous equations \begin{...
37 views

### Why do semiconductor lasers become weaker after extended use (not due to battery)?

Why do semiconductor lasers become less bright as they are used for longer periods of time (assuming their battery is full)? Does it have something to do with the PN junction reaching some kind of ...