Halliday, Resnick & Walker — Magnetic Fields: Problem 34

34 At time \(t_1\), an electron is sent along the positive direction of an x axis, through both an electric field \(\vec{E}\) and a magnetic field \(\vec{B}\), with \(\vec{E}\) directed parallel to the y axis. Figure 28-36 gives the y component \(F_{net,y}\) of the net force on the electron due to the two fields, as a function of the electron’s speed \(v\) at time \(t_1\). The scale of the velocity axis is set by \(v_s = 200.0 \text{ m/s}\). The x and z components of the net force are zero at \(t_1\). Assuming \(B_x = 0\), find (a) the magnitude \(E\) and (b) \(\vec{B}\) in unit-vector notation.