# Recent content by sam_p_r

1. ### Physics MSc/phd vs. Maths phd

I'm doing my undergraduate course in physics and getting good grades and enjoying it, especially the theoretical side. I'm definitely going to do postgraduate study, but I'm tempted switch to maths to do applied mathematics (fluid dynamics, chaotic systems etc.). Does anyone know much about...
2. ### De Broglie Wavelength - How does this hold for slow objects?

So what you're saying is that it only applies (in the exact lambda=h/p) for relativistic particles? (as its the only time where you can neglect mc^2). Because in many examples in textbooks it applies the formula to non-relativistic conditions.
3. ### De Broglie Wavelength - How does this hold for slow objects?

That E does not equal cp, it equals the square root of (cp)^2 + (mc^2)^2. So for de broglie equation, you have to neglect mc^2, which I can see as reasonable if it is very small in comparison to cp, but there are many occasions where it wont be. de broglie combines E=hc/lambda and E=cp, So...
4. ### De Broglie Wavelength - How does this hold for slow objects?

OK so you get to the matter wave equation 'lambda = h / p' using E=cp - which describes the energy for massless particles. I can understand this holding for when cp>>mc^2 , but not for when the mc^2 is comparible. Any help?
5. ### Kenitic vs. Static friction

But if the chemical composition changes, then the question has no value because the coeffecient of friction is between the two surfaces, and a surface has changed. ie. all you would be saying is that the kinetic friction is higher between these two surfaces than the static friction between these...