Q. An ideal pendulum was oscillating with an amplitude 60 degree inside a stationary elevator.
when pendulum was passing through equilibrium position the lift suddenly starts moving upward with an acceleration a=g . Find the new angular amplutude of the oscillation.

Interesting question, although the wording is a bit ambiguous. I hope you know whether the term "amplitude" here is measured from vertical to one exrtreme, or between extremes. To solve - I suggest using conservation of energy principles.