If two objects, A and B, moved towards each other in a single plane, with A having a larger mass and magintude of velocity than B, the result of the collision would be B turning around 180° to continue it's movement, meaning B would be completely stationary at the instant of the turn around. Assuming there is no compression in the objects, both objects would have a velocity of 0 at this instant, causing the net momentum to be 0.

Have I just disproven Conservation of Momentum?

I was watching a lecture on quantum mechanics by Prof. Leonard Susskind, and one of the audience asked about colour charge.  Susskind said something like it is not really coloured, it is just a label applied (I think) by Nambu, and he said spin was similair.

Is spin just a confusing name, or do quanta actually spin?  And what is the meaning of the spin states, how can an electron have 1/2 spin or a nucleus 7/2 spin etc.?

If spin is just an operation, then by some method of rotation we obtain a spin quantum number, but surely there are many symmetry operators that give rise to the same change in the spin state.  And if we imagine spin like a sphere moving about a certain axis, then what happens if we look from the point of view of another axis?

This seems too ambiguous a label considering that (from what I understand!) the best description we have of any fundamental particle is just an energy density probability function.  And if we can only think of particles as energies (or vibrating strings), how is it that energy composes matter in this way?

Particle accelerators such as that at CERN accelerate particles to high speeds before colliding them and measuring the particles given off.  However it is almost always protons that are collided, or ions or neutrons. Why doesn't anyone ever collide electrons?  Even if you did collide electrons, what sort of things would you see given off?

EDIT:

thanks for the answer, i'm also interested in what sort of particles are formed from electron collisions and how much energy is needed to form these particles.

In a vacuum, virtual particles are constantly appearing and annihilating, is this also going on inside my vacuum cleaner?

When physicists first split the atom by firing a proton at it, how did they a/ get a proton in the first place, and b/ know they were firing a proton, since they had not yet split the atom?

Recently I have heard, from the new scientist mag, of a particle called a Higs Boson. I realise that it can be in more than one place at the same time. What I don't understand is, how is that physically possible.

Is gravity some kind of pure energy? If yes, how does it affect the world around it in such a large way? If no, how it is "transported" around the universe?

I know that light can travel in waves, but what makes up those waves? Is it molecules or what?