Question

Length of a simple pendulum is $2m$ and mass of its bob is $2kg$ if the tension in the string exceeds $100N$, it will break. If $g=10m{s}^2$ and the bob is whirled in a horizontal plane, the maximum angle through which the sting can make vertical during rotation is

• A. $co{s}^{-1}\left(5/2\right)$
• B. $co{s}^{-1}\left(2/5\right)$
• C. $co{s}^{-1}\left(1/5\right)$
• D. $co{s}^{-1}\left(1/10\right)$

Answer 1

The correct option is C $co{s}^{-1}\left(1/5\right)$

$\frac{Forcebalanceinverticaldirection}{T\cos \theta =mg}$

$\frac{\cos \theta =mg}{T_{max}}=\frac{20}{100}=\frac{1}{5}$

$\theta ={\cos }^{-1}\left(1/5\right)$.