Question

The displacement of a particle starting from rest $(att=0)$ is given by $s=6t^2-t^3$. The time at which the particle will attain zero velocity again is

• A. $4s$
• B. $8s$
• C. $12s$
• D. $16s$

Answer 1

The correct option is A $4s$

$s={6t}^2-t^3$

$v=\frac{ds}{dt}=12t-3t^2$

If. $v=0$, then$12t-3t^2=0$ .... $\left(A\right)$

Solving, we get $t=0secort=4sec$

Thus, the particle will attain zero velocity at the time of $4seconds$.