Answers B and D are true.
lf a heavy point mass is suspended by a weightless, inextensible and perfectly flexible string from a rigid support, then this arrangement is called simple pendulum.
In practice, however, these requirements cannot be fulfilled. So we use a practical pendulum.
A practical pendulum consists of a small metallic solid sphere suspended by a fine silk thread from a rigid support. This is the practical simple pendulum which is nearest to the ideal simple pendulum.
Note :
The metallic sphere is called the bob.
When the bob is displaced slightly to one side from its mean position and released, it oscillates about its mean position in a vertical plane.
U need an insulator to prevent the shock passing through , that's why there is a plastic sheet covering the copper wires so that it can prevent the electricity passing through as plastic is an insulator and does not conduct electricity
Force is all the same, but pressure will be higher on 3cm
