I imagine it wouldn't be too friendly to read. We're used to 3D illustrations in our physics textbooks, reinforcement through applications, etc. I haven't read the principia.
I think to feel and be moved by fundamental physics concepts like inertia, you need to go out, experiment and reason...
Electrons are, according to our current understanding, fundamental particles (Leptons). Protons and Neutrons are made up of smaller particles called quarks.
Moving charges create a magnetic field around themselves. Considering the fact that electrons are 'moving' around the nucles (Not a complete picture of how it 'really' works, really), everything should have a magnetic field. However, the field ought to be too small to detect.
Does everything...
General quadratic equation: y=ax^2 + bx + c
Derivative: y' = 2ax + b
At the vertex, the derivate equals to zero. Use this fact and simultaneous equations to arrive at the equation.
http://en.wikipedia.org/wiki/Rayleigh_scattering
The amount of scattering depends on the frequency of the light. Blue light, having a higher frequency, scatters more than lower frequencies (Which pretty much pass straight through the atmosphere). This scattering of blue light more than the...