Question

A pendulum swings through an angle of ${30}^{\circ }$ and describes an arc 8.8 cm in length. Find the length of the pendulum.(Use $\pi$ = 22/7)

Answer 1

Given : here $\theta ={30}^{\circ }$ , length of arc $=8.8cm$

$\therefore I=\frac{\theta }{360}\times 2\pi r$

$\Rightarrow I=\frac{30}{360}\times 2\times \frac{22}{7}\times r=\frac{8.8\times 6\times 7}{22}cm$ $=16.8cm$