1. The problem statement, all variables and given/known data The free end of a simple pendulum is attached to the ceiling of a box. The box is taken to a height and the pendulum is oscillated. When the bob is at its lowest point, the box is released to fall freely. As seen from the box during this period, the bob will a)continue its oscillation as before b)stop c)will go in a circular path d)move on a straight line 2. Relevant equations 3. The attempt at a solution When the box starts falling freely g effective is 0 as seen inside the box. That means the time period of oscillation tends to infinity. It means the pendulum must stop. But thats incorrect. The correct option is c).