Q. A $10\ kg$ body hangs at rest from a rope wrapped around a cylinder $0.2\ m$ in diameter. The torque applied about the horizontal axis of the cylinder is
A) $98\ N$-$m$
B) $19.6\ N$-$m$
C) $196\ N$-$m$
D) $9.8\ N$-$m$
Explanation
(d) $\tau = r \times F$
$= r \times T$
$= r \times m \times g$
$= 0.1 \times 10 \times 9.8$
$= 9.8\ N$-$m$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.