Predict/Calculate When a charged particle enters a region of uniform magnetic field, it follows a circular path, as indicated in FlGURE $22-44 .$ (a) Is this particle positively or negatively charged? Explain. (b) Suppose that the magnetic field has a magnitude of $0.180 \mathrm{T},$ the particle's speed is $6.0 \times 10^{6} \mathrm{m} / \mathrm{s},$ and the radius of its path is 52.0 $\mathrm{cm} .$ Find the mass of the particle, given that its charge has a magnitude of $1.60 \times 10^{-19} \mathrm{C}$ . Give your result in atomic mass units, u, where $1 \mathrm{u}=1.67 \times 10^{-27} \mathrm{kg}$.