Walker, Halliday & Resnick — Magnetic Fields Due to Currents: Problem 53

53 Figure 29-58 shows a snapshot of a proton moving at velocity \(\vec{v} = (-380 \text{ m/s})\hat{j}\) toward a long straight wire with current \(i = 470 \text{ mA}\). At the instant shown, the proton's distance from the wire is \(d = 2.89 \text{ cm}\). In unit-vector notation, what is the magnetic force on the proton due to the current?