question_answer

The displacement of a particle at time t is given by \[\vec{x}=a\hat{i}+bt\hat{j}+\frac{c}{2}{{t}^{2}}\hat{k}\] where a, b and c are positive constants. Then the particle is [NDA]

A) accelerated along \[\frac{18}{5}\] direction

B) decelerated along \[\frac{18}{5}\] direction

C) decelerated along \[\hat{j}\] direction

D) accelerated along \[\hat{j}\] direction