Q) The free end of a simple pendulum is attached to the ceiling of a box. The box is taken to a height and then the pendulum is oscillated.When the bob is at is lowest point , the box is allowed to fall freely. As seen from the box during this period, the bob will :

A) continue its oscillations as before

B) stop

C) will go in a circular path

D) move on a atraight line

Please explain me how the answer come. Thnks a lot in advance.

Dear Ramsing

when box is falling with acceleration g then  one pshedo force(mg) will act in the bob in the apposite direction

so when bob is at the position as shown in figure then there is no retarding force( weight os bob and pshedo force will cancel each other)

 onlt tension in string and centrifugal force will act but these force are perpendicular to the direction of velocity so it will not change the magtitude of velocity it will only change  the direction.

so bob will start moving in the circle.

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Badiuddin

because the pivot is under free falling so there will b only tension wrt pivot and it will act as centripital force and so it will go under circular motion