Question

The position of a particle moving along x-axis given by $x=(-2t^3+3t^2+5)m$. The acceleration of particle at the instant its velocity becomes zero is

• A. $12m/s^2$
• B. $-12m/s^2$
• C. $-6m/s^2$
• D. Zero

Answer 1

The correct option is C $-6m/s^2$

The position of a particle moving along x-axis is given by

$x=(-2t^3+3t^2+5)m$

Velocity, $v=\frac{dx}{dt}=0$

$-6t^2+6t=0$. . . . . . .(1)

$6t(-t+1)=0$

$-t+1=0$

$t=1sec$

Acceleration, $a=\frac{dv}{dt}$

$a=-12t+6$

$a{|}_{t=1sec}=-12\times 1+6$

$a{|}_{t=1sec}=-6m/s^2$

The correct option is C.