Opinions wanted: is the fact that that talks about a density matrix sufficient physical context to make it on topic here?

I vote yes @DavidZ

@IceBoy well it's not really a vote - why do you say yes?

A car skids to a stop with constant acceleration. How much kinetic energy does it lose at the midpoint of the skid? So I figured the velocity at the midpoint is half the initial velocity, thus where $\vec{V_m}$ is the midpoint's velocity: $$\triangle W = \frac{m(\vec{V_i} - \vec{V_m})}{2}$$ which becomes: $$\triangle W = \frac{m(\vec{V_i} - \sqrt{\frac{\vec{V_i}^2}{2}})}{2}$$ and then: $$\triangle W = \frac{m\vec{V_i}(1 - \frac{1}{\sqrt{2}})}{2}$$ Does this make sense?

@DavidZ Questions "devoid of physics or references to physics" are to be considered off-topic, since there is at least a reference, this should remain on topic.

Physics SE must be doing something right: we're getting a steady stream of people who want to push their pet theories.

@dmckee Now the question is - do they think that we're easy targets, or do they think we're a challenge?

@IceBoy Awwyes! Finally

Hi, I'm applying to an undergraduate programme. As part of my application, I am submitting a research supplement, but it requires a letter of recommendation from a senior supervisor/researcher. However, I have done the work alone without supervision, and I don't have any contacts in academics. Does anyone have any suggestions on what I can do to find someone?