Question 1079694
HINTS:
In physics, the period of a pendulum is supposed to be a constant,
depending on the length of the string, {{{L}}} ,
and the acceleration of gravity, {{{g=about}}}{{{9.8}}}{{{m/s^2}}} :
{{{T=2pi*sqrt(L/g)}}} .
The period is the time between two consecutive times the pendulum is closest to the wall.
 
If you know the pendulum started at {{{A[0]}}} away from the vertically down equilibrium position,
swinging in an arc of radius {{{L}}} ,
you can calculate the initial angle between string and the vertical.
 
Assuming the ceiling is horizontal, you can relate that to
the initial angle between the string and the ceiling.