The velocity of a particle of charge $+4.0 \times 10^{-9} \mathrm{C}$ and mass $2 \times 10^{-4} \mathrm{~kg}$ is perpendicular to a $0.1\text{-tesla}$ magnetic field. If the particle's speed is $3 \times 10^{4} \mathrm{~ms}^{-1}$, what is the acceleration of this particle due to the magnetic force?