Q. The instantaneous angular position of a point on a rotating wheel is given by the equation θ(t) = 2t³ − 6t². The torque on the wheel becomes zero at
A) t = 2 s
B) t = 1 s
C) t = 0.2 s
D) t = 0.25 s
Explanation
[Solution from source] Torque is zero when angular acceleration is zero: α = d²θ/dt² = 12t − 12 = 0, so t = 1 s. Setting the angular velocity 6t² − 12t to zero instead gives t = 2 s, which is the trap. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.