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]

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

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

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

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

The displacement of a particle at time t is given by \[\vec{x}=a\hat{i

1.	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
Answer» B. decelerated along \[\frac{18}{5}\] direction