Function magnetic_force_magnitude_on_charge 

pub fn magnetic_force_magnitude_on_charge(
    charge: f64,
    speed: f64,
    magnetic_flux_density: f64,
    angle_radians: f64,
) -> Option<f64>

Computes the magnitude of magnetic force on a moving charge.

Formula: |F| = |q| * speed * |B| * sin(theta)