Q.
The instantaneous angular-position of a point on a rotating wheel is given by the equation $\theta(t) = 2t^{3} - 6t^{2}$. The torque on the wheel becomes zero at
A) $t = 2s$
B) $t = 1s$
C) $t = 0.2\ s$
D) $t = 0.25\ s$
Explanation
(b) Torque zero means, $\alpha$ zero
$\therefore\frac{d^{2}\theta}{dt^{2}} = 0 \Rightarrow 12t - 12 = 0$
$\therefore t = 1$ second
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.