Q. A string of length $l$ is fixed at one end and caries a mass $m\ $at the other end. The string makes $2/\pi$ rps around a vertical axis through the fixed end. What is the tension in string?
A) $m\ l$
B) 16 $m\ l$
C) $4\ m\ l$
D) $2\ m\ l$
Explanation
(b) $T\sin{\theta = mr\omega^{2} = m\left( l\sin\theta \right)\omega^{2}}$
or $T = ml\omega^{2} = ml\left( 2\pi \times \frac{2}{\pi} \right)^{2} = 16ml$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.