Recent content by Hootenanny

The velocity of the plane relative to what?

There is insufficient information to answer your question. We need the velocity of the plane relative to some reference point.

Afraid not, without knowing the temperature distribution at a specific time you aren't going to obtain a (non-trivial) unique solution. The former specifies the temperature on the spatial boundaries of the domain (in this case x=-1 and x=1). The latter specifies the temperature distribution at...

Your equation is the 1D heat equation, the solutions of which are very well known and understood. A google search should yield what you need. P.S. You will also need some kind of initial condition.

I believe it indicates that the user in question is one of your designated "friends".

You will want to start by checking this:

Indeed they do! :approve:

Excellent! So what happens if you first operate on \psi with A_1, followed by A_2? Compare this with what happens when you do it the other way round.

Yes. So, we have (preserving the index): A_1 \psi = a_1\psi. Suppose we now have a second hermitian operator, A_2. Can you write a similar equation?

If \psi is an eigenfunction of the hermitian operator A_1, what does this mean? Can you write the eigenvalue problem?

So we are left with \Delta U = GM_E m \left(\frac{1}{R} - \frac{1}{R+h}\right). Simply plug the numbers in and you should get your result.

Yes. One would need to go back to Newton's law of gravitation and compute \Delta U = \int_{R}^{R+h} \frac{GM_E m}{r^2}\;\text{d}r, where R is the radius of the Earth, ME is the mass of the Earth, m is the mass of the man and h is the height of Everest.

First you must understand the Lorentz transformations: http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/ltrans.html#c2 Then you can take a look at length contraction & time dilation: http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/tdil.html Such explanations a notoriously difficult and...

Welcome to Physics Forums. The invariance in the speed of light was postulated by Einstein in the early 20th century. Einstein deduced (for want of a better word) this from the lack of an aether (i.e. the fact that light doesn't need a medium to propagate through). This invariance has been...

We are veering wildly from philosophy to utter nonsense here. I'm going to lock the thread, pending moderation.