Question

A pendulum swings through an angle of 30${}^o$ and describes an arc 8.8 cm in length. Find the length of the pendulum.

Answer 1

Here,

$\theta ={30}^o$

$l=arc=8.8cm$

$l=\frac{\theta }{{360}^o}\times 2\pi r$

$8.8=\frac{30}{360}\times 2\frac{22}{7}\times r$

$r=\frac{8.8\times 6\times 7}{22}=16.8cm$