What is the to and fro motion of a simple pendulum called?

Answer the following questions : What is the frequency of oscillation of a simple pendulum mounted in a cabin that is freely falling under gravity ?

Why are vibrations of a simple pendulum damped?

What is the effect on the time period of a simple pendulum, if the mass of the bob is doubled?

What is simple harmonic motion and prove a simple pendulum oscillates simple harmonically?Also find a relation for its frequency.