Velocity of a particle is  $\mathbf{v}=(2\hat{\mathbf{i}}+3\hat{\mathbf{j}}-4\hat{\mathbf{k}})\mathrm{m}/\mathrm{s}$ and its acceleration is zero. State whether it is $1-D, 2-D or 3-D$ motion?

Since, acceleration of the particle is zero. Therefore, it is uniform motion or motion in a straight line. So, it is one dimensional motion