Q. A particle is moving in a straight line. At time $t$, the distance between the particle from its starting point is given by $x = t - 6t^{2} + t^{3}.Its$ acceleration will be zero at

A) $t = 1\$unit time
B) $t =$2 units time
C) $t = 3\$units time
D) $t = 4\$units time
Explanation

(b)
Given, $x = t - 6t^{2} + t^{3}$
On differentiating, w. r. t. x, we get
$\frac{dx}{dt} = 1 - 12t + 3t^{2}$
Again, differentiating, we get
$\ \ \frac{d^{2}x}{dt^{2}} = - 12 + 6t\$
When $\ \ \ \frac{d^{2}x}{dt^{2}} = 0 \Rightarrow t = 2$units time

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.