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

Step-by-step solution

When the box falls freely, its acceleration is g downwards. In the frame of reference of the box, a pseudo force mg acts upwards on the bob, which exactly cancels the true weight mg acting downwards. Thus, the effective acceleration due to gravity in the frame of the box is g_ eff = 0 . At the lowest point of oscillation, the bob has a horizontal velocity v relative to the box. Since g_ eff = 0 , there is no tangential force to change the speed of the bob. The tension in the string provides the necessary centripeta