Question

If a simple pendulum is falling freely under gravitational force of attraction its time period will be

Answer 1

answer : time period will be ∞.

explanation : if a simple pendulum is falling freely under gravitational force of attraction, it shows bob is placed in non-inertial frame of reference. to make inertial frame of reference, applying Pseudo force just opposite direction of its motion and equal in magnitude.

so, pseudo force = -mg

and then, net acceleration acting on bob , a = Weight + pseudo force

= mg - mg = 0

now, time period, T = 2π√{l/a}

but a = 0, so, T = 2π√{l/0} → ∞

hence, time period of simple pendulum will be infinity. means bob completes one revolution infinite time of interval.