What will be the frequency of a simple pendulum in a cabin that is falling freely under gravity?
Answers
hey,
The answer is zero - the pendulum will not be in oscillation.
Even if the pendulum had been in oscillation before the commencement of the cabin’s free fall, this oscillation will cease very quickly once the free fall begins.
Hitherto, the pendulum swing was due to three identifiable forces: 1) The downwardly directed force of gravity 2) The tension in the string 3) The angular momentum of the pendulum.
At the commencement of the cabin’s free fall, whereas the downwardly directed force of gravity still acts on the pendulum, the tension force in the string disappears because the cabin roof, presumably from which the pendulum hangs, is in free fall also and thus a “reaction” pull by the string becomes inexistent since there is an inexistent pull by the pendulum mass also, as both objects have zero motion relative to each other, nor is there a dynamic equilibrium of forces acting between them.