Mark it as brainlist answer
Let the pendulum is drawn to a side by a small angle ′θ′ and allowed free to oscillatioate in the veritcle plane. Then it will oscillate between the extreme position A and B with a displacement say 'X' at any given time. Let the bob is at onc extreme position say B. The force vertically acting downwards is weight W=mg.
its not a big deal but it is very difficult question to answer fast and i will follow the most popular of the country in a family friend and family to do in the process
find the height at acceleration due to gravity (g) becomes half of acceleration due to gravity at earth's surface(g0)