Abi physics: web forms by electrons in the homogeneous magnetic field

I have a question about a Physics task: A particle with charge q occurs at the speed v a a a homogeneous magnetic field with the flux density. Describe the shape of the path which passes through the particles and justify their statement exactly: - (. Angle betw v; B) If> 0 ° <<90 °

The solution I do not understand: There are apparently 2 Komponeten of v A is perpendicular to B and forces the particles into a circular path.. The second component is in the direction of B, there is a uniform movement in the direction of B.

Why are there by now v 2 components? What are these two components? a v can not have 2 directions?

grateful for any help :)

The best answer

You can split into 2 components the vector of v: depending entering angle you have more or less motion perpendicular or parallel to the magnetic field. But only the speed showing perpendicular to the magnetic pays off in the Lorentz force a (F = B * v * q). This formula applies to v perpendicular to B. If the entry angle <90 * applies: F = q * B * v * cos (alpha)

The motion of the electron is the superposition of the circular motion in the plane perpendicular to the magnetic field lines (caused by the Lorentz force) and a uniform translation in the direction of the magnetic field lines. The electron moves consequently along a helix.