Q. An object of mass 5 kg is whirled round in a vertical circle of radius 2 m with a constant speed of $6\ ms^{- 1}$. The maximum tension in the string is
A) 152 N
B) 139 N
C) 121 N
D) 103 N
Explanation
(b) Here, $m = 5\ kg,r = 2m,v = 6\ ms^{- 1}$
The tension is maximum at the lowest point
$T_{\max} = mg + \frac{mv^{2}}{r}$
$= 5 \times 9.8 + \frac{5 \times 6 \times 6}{2}$
$= 139$N
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.