Answer:
T = 9.19 seconds
Explanation:
It is given that,
Length of the pendulum, l = 21 m
We need to find its time period. We know that the time period of the pendulum is given by :
[tex]T=2\pi \sqrt{\dfrac{L}{g}}[/tex]
g is acceleration due to gravity
So,
[tex]T=2\pi \sqrt{\dfrac{21}{9.8}}\\\\T=9.19\ s[/tex]
So, the period of the pendulum is 9.19 seconds.