For a simple pendulum making a small angle
#l#is its length and #g#is acceleration due to gravity.
Physically it may not be possible to realize a pendulum with
However, there would arise situations where
it is same as running a pendulum in gravity free region,
Pendulum in a freely falling lift is an example of such a situation. In the frame of reference of lift we need to account for acceleration of so that so that Newton's Laws of motion are valid and could be applied. Hence, a pseudo force equal and opposite to downward force due to