Question

A ball of mass 0.6kg attached to a light inextensible string rotates in a vertical circle of radius 0.75m such that it has speed of 5 m/s when the string is horizontal. Tension in string when it is horizontal on other side is:

$(g=10m{s}^{-2})$

• A. $30N$
• B. $26N$
• C. $20N$
• D. $6N$

Answer 1

Answer: (C)

$20N$

Given: $m=0.6kg;R=0.75m$
Force equilibrium
$T=\frac{m{v}^2}{R}$

$=\frac{\left(0.6\right)(5{)}^2}{\left(0.75\right)}$

$=20N$