A charge $q = -0.3 \mu C$ has a velocity of 1500000 m/s at $45^\circ$ to the $+x$ axis in the $xz$ plane, with a positive $x$ and $z$ component. There is a magnetic field of magnitude 0.06 T.
a) If $\mathbf{B}$ is along the $+z$ axis, what is the force on the charge?
0.01909 N along the $+y$ axis
b) Now the velocity and the magnitude of the B field is kept the same, but the direction of the B field is changed. If the force on the charge is $3 \times 10^{-3}$ N along $+y$ axis, what is the direction of $\mathbf{B}$?
degrees from the $+z$ axis in the $xz$ plane.
