A pendulum swings through an angle of 30∘ and describes an arc 8.8 cm in length. Find the length of pendulum in cm.
16.8
Let r be the length of the pendulum.
Given: Length of arc = 8.8 cm.
∠AOB=30∘
Length of an arc of a sector of an angle θ=θ360×2πr
⇒8.8=30°360°×2×227×r
r=8.8×2111=16.8 cm